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2019 Volume 30 Issue 12
2019, 30(12): 1995-1995
doi: 10.1016/j.cclet.2019.06.034
Abstract:
2019, 30(12): 1996-2002
doi: 10.1016/j.cclet.2019.02.002
Abstract:
This short review is dedicated to celebrate Prof. Shoukuan Fu's 80th birthday by discussing several of my accomplished projects over the past twenty years, which all applied radical polymerization in aqueous dispersed media for producing polymers with branched structures. These projects include the use of microemulsion polymerization for syntheses of fluorescent nanoparticles, hairy nanoparticles and hyperbranched polymers; the use of miniemulsion polymerization for synthesis of star polymers and light-emitting nanoparticles; the use of seeded emulsion polymerization for synthesis of hairy nanoparticles and hyperstar polymers; and the use of precipitation polymerization for synthesis of hollow polymer nanocapsules. Discussion of these projects demonstrates intriguing features of polymerization in biphasic dispersed media via either conventional radical polymerization or controlled radical polymerization to effectively regulate the branched structure of functional polymers.
This short review is dedicated to celebrate Prof. Shoukuan Fu's 80th birthday by discussing several of my accomplished projects over the past twenty years, which all applied radical polymerization in aqueous dispersed media for producing polymers with branched structures. These projects include the use of microemulsion polymerization for syntheses of fluorescent nanoparticles, hairy nanoparticles and hyperbranched polymers; the use of miniemulsion polymerization for synthesis of star polymers and light-emitting nanoparticles; the use of seeded emulsion polymerization for synthesis of hairy nanoparticles and hyperstar polymers; and the use of precipitation polymerization for synthesis of hollow polymer nanocapsules. Discussion of these projects demonstrates intriguing features of polymerization in biphasic dispersed media via either conventional radical polymerization or controlled radical polymerization to effectively regulate the branched structure of functional polymers.
2019, 30(12): 2123-2131
doi: 10.1016/j.cclet.2019.09.043
Abstract:
The acidic gases such as SO2, NOx, H2S and CO2 are typical harmful pollutants and greenhouse gases in the atmosphere, which are also the main sources of PM2.5. The most widely used method of treating these gas molecules is to capture them with different adsorption materials, i.e., metal and nonmetallic materials such as MnO2, MoS2 and carbon-based materials. And doping transition metal atoms in adsorption materials are beneficial to the gas adsorption process. The first-principles calculation is a powerful tool for studying the adsorption properties of contaminant molecules on different materials at the molecular and atomic levels to understand surface adsorption reactions, adsorption reactivity, and structureactivity relationships which can provide theoretical guidance for laboratory researches and industrial applications. This review introduces the adsorption models and surface properties of these gas molecules on metal and nonmetallic surfaces by first-principles calculation in recent years. The purpose of this review is to provide the theoretical guidance for experimental research and industrial application, and to inspire scientists to benefit from first-principles calculation for applying similar methods in future work.
The acidic gases such as SO2, NOx, H2S and CO2 are typical harmful pollutants and greenhouse gases in the atmosphere, which are also the main sources of PM2.5. The most widely used method of treating these gas molecules is to capture them with different adsorption materials, i.e., metal and nonmetallic materials such as MnO2, MoS2 and carbon-based materials. And doping transition metal atoms in adsorption materials are beneficial to the gas adsorption process. The first-principles calculation is a powerful tool for studying the adsorption properties of contaminant molecules on different materials at the molecular and atomic levels to understand surface adsorption reactions, adsorption reactivity, and structureactivity relationships which can provide theoretical guidance for laboratory researches and industrial applications. This review introduces the adsorption models and surface properties of these gas molecules on metal and nonmetallic surfaces by first-principles calculation in recent years. The purpose of this review is to provide the theoretical guidance for experimental research and industrial application, and to inspire scientists to benefit from first-principles calculation for applying similar methods in future work.
2019, 30(12): 2132-2138
doi: 10.1016/j.cclet.2019.09.041
Abstract:
Herein we summarized some clean preparation examples to emphasize the concept of dual roles design (or named as "two birds one stone strategy") in green and sustainable chemistry. In those examples, the reactants and/or solvent play dual roles rendering a cleaner organic preparation process. Consequently, both the chemical waste and manufacturing cost could be reduced.
Herein we summarized some clean preparation examples to emphasize the concept of dual roles design (or named as "two birds one stone strategy") in green and sustainable chemistry. In those examples, the reactants and/or solvent play dual roles rendering a cleaner organic preparation process. Consequently, both the chemical waste and manufacturing cost could be reduced.
2019, 30(12): 2139-2146
doi: 10.1016/j.cclet.2019.04.057
Abstract:
The electrochemical advanced oxidation processes (EAOPs) have been extensively applied in the treatment of organic pollutants degradation. Herein, the mini review provides the coupling systems about EAOPs and different oxidants (e.g., persulfate (PS), peroxymonosulfate (PMS), and ozone (O3)), including EAOPs-PS systems, EAOPs-PMS systems, EAOPs-peroxone systems, and photoelectro-oxidants systems, for the organic compounds degradation. The coupling system of EAOPs with oxidants is an effective way to improve the generated free radicals (e.g., HO· and SO4·-) concentration and to accelerate pollutant degradation. In this review, we make a summary of the homogeneous and heterogeneous EAOPs-oxidant processes. The reaction mechanisms of EAOPs combined with different oxidants are elucidated in detail, as well as the synergistic effect for improving the degradation and mineralization efficiency.
The electrochemical advanced oxidation processes (EAOPs) have been extensively applied in the treatment of organic pollutants degradation. Herein, the mini review provides the coupling systems about EAOPs and different oxidants (e.g., persulfate (PS), peroxymonosulfate (PMS), and ozone (O3)), including EAOPs-PS systems, EAOPs-PMS systems, EAOPs-peroxone systems, and photoelectro-oxidants systems, for the organic compounds degradation. The coupling system of EAOPs with oxidants is an effective way to improve the generated free radicals (e.g., HO· and SO4·-) concentration and to accelerate pollutant degradation. In this review, we make a summary of the homogeneous and heterogeneous EAOPs-oxidant processes. The reaction mechanisms of EAOPs combined with different oxidants are elucidated in detail, as well as the synergistic effect for improving the degradation and mineralization efficiency.
2019, 30(12): 2147-2150
doi: 10.1016/j.cclet.2019.05.002
Abstract:
Lignocellulosic biomass is an abundant and environment-friendly source for renewable energy production. The value and application of biochar, which is obtained from the thermochemical conversion of biomass, is increasing rapidly because of its high carbon content and porosity. The property of biochar, such as surface area, porosity, and number of functional groups, can be improved by controlling the conditions of biomass conversion, biochar activation, and functionalization methods. The production and activation of biochar as well as its potential use for soil remediation, pollutant adsorption, and biorefinery have been reviewed extensively over recent decades. This paper provides a conceptual approach for biochar production and activation together with its application as a catalyst for biorefineries and the removal of environmental contaminants.
Lignocellulosic biomass is an abundant and environment-friendly source for renewable energy production. The value and application of biochar, which is obtained from the thermochemical conversion of biomass, is increasing rapidly because of its high carbon content and porosity. The property of biochar, such as surface area, porosity, and number of functional groups, can be improved by controlling the conditions of biomass conversion, biochar activation, and functionalization methods. The production and activation of biochar as well as its potential use for soil remediation, pollutant adsorption, and biorefinery have been reviewed extensively over recent decades. This paper provides a conceptual approach for biochar production and activation together with its application as a catalyst for biorefineries and the removal of environmental contaminants.
2019, 30(12): 2151-2156
doi: 10.1016/j.cclet.2019.05.063
Abstract:
In this review, the recent development about using DESs as green solvents in transition metal catalyzed organic reactions was highlighted. Firstly, the development of DESs was simply introduced. After presenting the advantages of DESs, transition metals catalyzed organic reactions using DESs as green solvents were classified and introduced in detail. Different transition metals such as Au, metal impregnated on magnetite, Pd and Ru catalyzed organic reactions proceeded smoothly in DESs and gave corresponding products in good yields. And in some cases, the catalytic systems could be recycled up to several times without any decrease in activity.
In this review, the recent development about using DESs as green solvents in transition metal catalyzed organic reactions was highlighted. Firstly, the development of DESs was simply introduced. After presenting the advantages of DESs, transition metals catalyzed organic reactions using DESs as green solvents were classified and introduced in detail. Different transition metals such as Au, metal impregnated on magnetite, Pd and Ru catalyzed organic reactions proceeded smoothly in DESs and gave corresponding products in good yields. And in some cases, the catalytic systems could be recycled up to several times without any decrease in activity.
2019, 30(12): 2003-2008
doi: 10.1016/j.cclet.2019.01.019
Abstract:
Mesoporous late-transition metal oxides have great potential in applications of energy, catalysis and chemical sensing due to their unique physical and chemical properties. However, their synthesis via the flexible and scalable soft-template method remain a great challenge, due to the weak organic-inorganic interaction between the frequently used surfactants (e.g., Pluronic-type block copolymers) and metal oxide precursors, and the low crystallization temperature of metal oxides. In this study, ordered mesoporous NiO with dual mesopores, high surface area and well-interconnected crystalline porous frameworks have been successfully synthesized via the facile solvent evaporation-induced co-assembly (EICA) method, by using lab-made amphiphilic diblock copolymer polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) as both the structure-directing agent (the soft template) and macromolecular chelating agents for nickel species, THF as the solvent, and nickel acetylacetonate (Ni(acac)2) as inorganic precursor. Similarly, by using Ni(acac)2 and Fe(acac)3 as the binary precursors, ordered mesoporous Fedoped NiO materials can be obtained, which have bimodal mesopores of large mesopores (32.5 nm) and secondary mesopores (4.0-11.5 nm) in the nanocrystal-assembled walls, high specific surface areas (~74.8 m2/g) and large pore value (~0.167 cm3/g). The obtained mesoporous Fe-doped NiO based gas sensor showed superior ethanol sensing performances with good sensitivity, high selectivity and fast response-recovery dynamics.
Mesoporous late-transition metal oxides have great potential in applications of energy, catalysis and chemical sensing due to their unique physical and chemical properties. However, their synthesis via the flexible and scalable soft-template method remain a great challenge, due to the weak organic-inorganic interaction between the frequently used surfactants (e.g., Pluronic-type block copolymers) and metal oxide precursors, and the low crystallization temperature of metal oxides. In this study, ordered mesoporous NiO with dual mesopores, high surface area and well-interconnected crystalline porous frameworks have been successfully synthesized via the facile solvent evaporation-induced co-assembly (EICA) method, by using lab-made amphiphilic diblock copolymer polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) as both the structure-directing agent (the soft template) and macromolecular chelating agents for nickel species, THF as the solvent, and nickel acetylacetonate (Ni(acac)2) as inorganic precursor. Similarly, by using Ni(acac)2 and Fe(acac)3 as the binary precursors, ordered mesoporous Fedoped NiO materials can be obtained, which have bimodal mesopores of large mesopores (32.5 nm) and secondary mesopores (4.0-11.5 nm) in the nanocrystal-assembled walls, high specific surface areas (~74.8 m2/g) and large pore value (~0.167 cm3/g). The obtained mesoporous Fe-doped NiO based gas sensor showed superior ethanol sensing performances with good sensitivity, high selectivity and fast response-recovery dynamics.
2019, 30(12): 2009-2012
doi: 10.1016/j.cclet.2019.02.006
Abstract:
Magnetic polyphosphazene (MPZS) particles coated by Ag nanoparticles (MPZS-Ag) have been developed as surface enhanced Raman spectroscopy (SERS) substrates for sensitive detection of melamine in aqueous solutions and milk samples. 5, 5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) was used as model analyte to test the SERS activity of the MPZS-Ag particles. The prepared MPZS-Ag particles possess both magnetic responsiveness and excellent SERS properties. SERS detection of different concentrations of melamine aqueous solutions and spiked milk samples were performed by the MPZS-Ag particles. The limit of detection (LOD) of the melamine in aqueous solutions was 10-7 mol/L (0.0126 mg/L) and 0.6 mg/L in real milk samples using the MPZS-Ag particles as SERS substrates. The LOD of the melamine are much lower than the safety values of Food and Drug Administration and Codex Alimentarius Commission. These results indicate that the MPZS-Ag particles have promising application prospect for SERS analysis in food safety fields.
Magnetic polyphosphazene (MPZS) particles coated by Ag nanoparticles (MPZS-Ag) have been developed as surface enhanced Raman spectroscopy (SERS) substrates for sensitive detection of melamine in aqueous solutions and milk samples. 5, 5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) was used as model analyte to test the SERS activity of the MPZS-Ag particles. The prepared MPZS-Ag particles possess both magnetic responsiveness and excellent SERS properties. SERS detection of different concentrations of melamine aqueous solutions and spiked milk samples were performed by the MPZS-Ag particles. The limit of detection (LOD) of the melamine in aqueous solutions was 10-7 mol/L (0.0126 mg/L) and 0.6 mg/L in real milk samples using the MPZS-Ag particles as SERS substrates. The LOD of the melamine are much lower than the safety values of Food and Drug Administration and Codex Alimentarius Commission. These results indicate that the MPZS-Ag particles have promising application prospect for SERS analysis in food safety fields.
2019, 30(12): 2013-2016
doi: 10.1016/j.cclet.2019.04.005
Abstract:
Photothermal therapy (PTT) has emerged as one of the promising cancer therapy approaches. As a representative photothermal agent (PTA), magnetite possesses many advantages such as biodegradability and biocompatibility. However, photothermal instability hampers its further application. Herein, we systematically synthesized three kinds of ferrite nanoparticles and detailedly investigated their photothermal effect. Compared with Fe3O4 and MnFe2O4 nanoparticles, ZnFe2O4 nanoparticles exhibited a superior photothermal effect. After preservation for 70 days, the photothermal effect of Fe3O4 and MnFe2O4 nanoparticles observably declined while ZnFe2O4 nanoparticles showed slight decrease. Furthermore, in vitro experiment, ZnFe2O4 nanoparticles showed little toxicity to cells and achieved outstanding effect in killing cancer cells under NIR laser irradiation. Overall, through synthesizing and studying three kinds of ferrite MFe2O4 nanoparticles, we obtained ferrites as PTAs and learned about their changing trend in photothermal effect, expecting it can inspire further exploration of photothermal agents.
Photothermal therapy (PTT) has emerged as one of the promising cancer therapy approaches. As a representative photothermal agent (PTA), magnetite possesses many advantages such as biodegradability and biocompatibility. However, photothermal instability hampers its further application. Herein, we systematically synthesized three kinds of ferrite nanoparticles and detailedly investigated their photothermal effect. Compared with Fe3O4 and MnFe2O4 nanoparticles, ZnFe2O4 nanoparticles exhibited a superior photothermal effect. After preservation for 70 days, the photothermal effect of Fe3O4 and MnFe2O4 nanoparticles observably declined while ZnFe2O4 nanoparticles showed slight decrease. Furthermore, in vitro experiment, ZnFe2O4 nanoparticles showed little toxicity to cells and achieved outstanding effect in killing cancer cells under NIR laser irradiation. Overall, through synthesizing and studying three kinds of ferrite MFe2O4 nanoparticles, we obtained ferrites as PTAs and learned about their changing trend in photothermal effect, expecting it can inspire further exploration of photothermal agents.
2019, 30(12): 2017-2020
doi: 10.1016/j.cclet.2019.04.019
Abstract:
Herein, AgLi1/3Sn2/3O2 with delafossite structure was prepared by treating the layered compound Li2SnO3 with molten AgNO3 via ion exchange of Li+ for Ag+. The structure characterization and the electrochemical performance of AgLi1/3Sn2/3O2 was thoroughly investigated. AgLi1/3Sn2/3O2 is found to possess stacking lamellar morphology, which means small electrochemical impedance and so facilitates charge transfer kinetics during the cycling. Compared with Li2SnO3, due to the introducing of excellent electrical conductivity of silver, AgLi1/3Sn2/3O2 exhibits improved electrochemical performance in terms of capacity, cycling stability and coulombic efficiency. The results show AgLi1/3Sn2/3O2 presents favorable specific capacity of 339 mAh/g at current density of 200 mA/g after 50 cycles and initial coulombic efficiency of 96%. Ex situ XRD analysis revealed the reaction mechanism of AgLi1/3Sn2/3O2 as an anode for lithium ion batteries.
Herein, AgLi1/3Sn2/3O2 with delafossite structure was prepared by treating the layered compound Li2SnO3 with molten AgNO3 via ion exchange of Li+ for Ag+. The structure characterization and the electrochemical performance of AgLi1/3Sn2/3O2 was thoroughly investigated. AgLi1/3Sn2/3O2 is found to possess stacking lamellar morphology, which means small electrochemical impedance and so facilitates charge transfer kinetics during the cycling. Compared with Li2SnO3, due to the introducing of excellent electrical conductivity of silver, AgLi1/3Sn2/3O2 exhibits improved electrochemical performance in terms of capacity, cycling stability and coulombic efficiency. The results show AgLi1/3Sn2/3O2 presents favorable specific capacity of 339 mAh/g at current density of 200 mA/g after 50 cycles and initial coulombic efficiency of 96%. Ex situ XRD analysis revealed the reaction mechanism of AgLi1/3Sn2/3O2 as an anode for lithium ion batteries.
2019, 30(12): 2021-2026
doi: 10.1016/j.cclet.2019.04.031
Abstract:
To develop a smart free-standing surface enhanced Raman scattering (SERS) substrate, silver nanoparticles (AgNPs) embedded temperature-sensitive nanofibrous membrane was fabricated by electrospinning their aqueous solution containing the copolymer poly(N-isopropylacrylamide-co-N-hydroxymethylacrylamide), followed by heat treatment to form crosslinking structure within its constituent nanofibers. To avoid negative effect of the additive like stabilizer and the reactant like reductant on their SERS efficiency, the AgNPs were in-situ synthesized through reducing Ag+ ions dissolved in the polymer solution by ultraviolet irradiation. The prepared hybrid nanofibrous membrane with high stability in aqueous medium can reach its swelling or deswelling equilibrium state within 15 seconds with the medium temperature changing between 25℃ and 50℃ alternately. When it was used as a free-standing SERS substrate, 10-12 mol/L of 4-nitrothiophenol in aqueous solution can be detected at room temperature, and elevating detection temperature can further lower its low detection limit. Since its generated SERS signal has desirable reproducibility, it can be used as SERS substrate for quantitative analysis. Moreover, the hybrid membrane as SERS substrate is capable of real-time monitoring the reduction of 4-nitrothiophenol into 4-aminothiophenol catalyzed by its embedded AgNPs, and the detected intermediate indicates that the reaction proceeds via a condensation route.
To develop a smart free-standing surface enhanced Raman scattering (SERS) substrate, silver nanoparticles (AgNPs) embedded temperature-sensitive nanofibrous membrane was fabricated by electrospinning their aqueous solution containing the copolymer poly(N-isopropylacrylamide-co-N-hydroxymethylacrylamide), followed by heat treatment to form crosslinking structure within its constituent nanofibers. To avoid negative effect of the additive like stabilizer and the reactant like reductant on their SERS efficiency, the AgNPs were in-situ synthesized through reducing Ag+ ions dissolved in the polymer solution by ultraviolet irradiation. The prepared hybrid nanofibrous membrane with high stability in aqueous medium can reach its swelling or deswelling equilibrium state within 15 seconds with the medium temperature changing between 25℃ and 50℃ alternately. When it was used as a free-standing SERS substrate, 10-12 mol/L of 4-nitrothiophenol in aqueous solution can be detected at room temperature, and elevating detection temperature can further lower its low detection limit. Since its generated SERS signal has desirable reproducibility, it can be used as SERS substrate for quantitative analysis. Moreover, the hybrid membrane as SERS substrate is capable of real-time monitoring the reduction of 4-nitrothiophenol into 4-aminothiophenol catalyzed by its embedded AgNPs, and the detected intermediate indicates that the reaction proceeds via a condensation route.
2019, 30(12): 2027-2031
doi: 10.1016/j.cclet.2019.04.052
Abstract:
PEGylated prodrug, covalent attaching polyethylene glycol (PEG) polymer chains to therapeutic drugs, is one of the most promising techniques to improve the water-solubility, stability, and therapeutic effect of drugs. In this study, three PEGylated acid-sensitive prodrugs DOX-PEG-DOX with different molecular weights, were prepared via Schiff-base reaction between aldehyde-modified PEG and the amino groups of doxorubicin (DOX). This kind of amphiphilic polymeric prodrug could be self-assemble into nanoparticles in aqueous solution. The average particle size and morphologies of the prodrug nanoparticles under different pH conditions were observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. It turned out that the nanoparticles could be kept stable in the physiological environment, but degraded in acidic medium. Subsequently, we also investigated in vitro drug release behavior and found that the prodrug had acid-sensitive property. The cytotoxicity and intracellular uptake assays revealed that the prodrugs could rapidly internalized by HeLa or HepG2 cells to release DOX and effectively inhibited the proliferation of the tumor cells, which have the potential for use in cancer therapy.
PEGylated prodrug, covalent attaching polyethylene glycol (PEG) polymer chains to therapeutic drugs, is one of the most promising techniques to improve the water-solubility, stability, and therapeutic effect of drugs. In this study, three PEGylated acid-sensitive prodrugs DOX-PEG-DOX with different molecular weights, were prepared via Schiff-base reaction between aldehyde-modified PEG and the amino groups of doxorubicin (DOX). This kind of amphiphilic polymeric prodrug could be self-assemble into nanoparticles in aqueous solution. The average particle size and morphologies of the prodrug nanoparticles under different pH conditions were observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. It turned out that the nanoparticles could be kept stable in the physiological environment, but degraded in acidic medium. Subsequently, we also investigated in vitro drug release behavior and found that the prodrug had acid-sensitive property. The cytotoxicity and intracellular uptake assays revealed that the prodrugs could rapidly internalized by HeLa or HepG2 cells to release DOX and effectively inhibited the proliferation of the tumor cells, which have the potential for use in cancer therapy.
2019, 30(12): 2032-2038
doi: 10.1016/j.cclet.2019.05.006
Abstract:
Nanocomposites constructed by combining mesoporous metal oxides and graphene have received tremendous attention in wide fields of catalysis, energy storage and conversion, gas sensing and so on. Herein, we present a facile interface-induced co-assembly process to synthesize the mesoporous WO3@graphene aerogel nanocomposites (denoted as mWO3@GA), in which graphene aerogel (GA) was used as a macroporous substrate, mesoporous WO3 was uniformly coated on both sides of graphene sheets through a solvent evaporation-induced self-assembly (EISA) strategy using diblock copolymer poly(ethylene oxide)-b-polystyrene (PEO-b-PS) as a template. The resultant mWO3@GA nanocomposites possess well-interconnected macroporous graphene networks covered by mesoporous WO3 layer with a uniform pore size of 19 nm, high surface area of 167 m2/g and large pore volume of 0.26 cm3/g. The gas sensing performance of mWO3@GA nanocomposites toward acetone and other gases was studied, showing a high selectivity and great response to acetone at low temperature of 150℃, which could be developed as a promising candidate as novel sensors for VOCs detection.
Nanocomposites constructed by combining mesoporous metal oxides and graphene have received tremendous attention in wide fields of catalysis, energy storage and conversion, gas sensing and so on. Herein, we present a facile interface-induced co-assembly process to synthesize the mesoporous WO3@graphene aerogel nanocomposites (denoted as mWO3@GA), in which graphene aerogel (GA) was used as a macroporous substrate, mesoporous WO3 was uniformly coated on both sides of graphene sheets through a solvent evaporation-induced self-assembly (EISA) strategy using diblock copolymer poly(ethylene oxide)-b-polystyrene (PEO-b-PS) as a template. The resultant mWO3@GA nanocomposites possess well-interconnected macroporous graphene networks covered by mesoporous WO3 layer with a uniform pore size of 19 nm, high surface area of 167 m2/g and large pore volume of 0.26 cm3/g. The gas sensing performance of mWO3@GA nanocomposites toward acetone and other gases was studied, showing a high selectivity and great response to acetone at low temperature of 150℃, which could be developed as a promising candidate as novel sensors for VOCs detection.
2019, 30(12): 2039-2042
doi: 10.1016/j.cclet.2019.05.017
Abstract:
Responsive polymers have been playing an increasingly important role in a wide variety of applications, such as biomedical materials and biosensors. Herein, we reported a dual-responsive polycarbonate (poly (MN-co-MSS)) based on the macrocyclic Sulfur/Nitrogen-substituted carbonate monomer (MSS/MN) via an enzyme-catalyzed ring-opening copolymerization and Lipase CA Novozym-435 as catalyst, with the disulfide and tertiary amine groups situated on the backbone. The structure of the random copolymers was confirmed by NMR and FTIR. In addition, size exclusion chromatography (SEC) results indicated that the copolymer had a symmetric peak and a relatively narrow polydispersity. Also, the random copolymers can self-assemble into micelle-like aggregates in water due to the hydrophilicity endowed by the amino groups, and the aggregates exhibited rich pH and GSH responsive behavior, which was verified by zeta masters instrument and dynamic light scattering (DLS). Moreover, transmission electron microscopy (TEM) demonstrated the morphology of the micellar aggregates and the variation subjected to the lower pH and GSH, and the responsive mechanism was elaborated. Therefore, these results highlighted a facile synthesis of the environment-responsive polymers and provided a novel GSH/pH responsive material platform for further application.
Responsive polymers have been playing an increasingly important role in a wide variety of applications, such as biomedical materials and biosensors. Herein, we reported a dual-responsive polycarbonate (poly (MN-co-MSS)) based on the macrocyclic Sulfur/Nitrogen-substituted carbonate monomer (MSS/MN) via an enzyme-catalyzed ring-opening copolymerization and Lipase CA Novozym-435 as catalyst, with the disulfide and tertiary amine groups situated on the backbone. The structure of the random copolymers was confirmed by NMR and FTIR. In addition, size exclusion chromatography (SEC) results indicated that the copolymer had a symmetric peak and a relatively narrow polydispersity. Also, the random copolymers can self-assemble into micelle-like aggregates in water due to the hydrophilicity endowed by the amino groups, and the aggregates exhibited rich pH and GSH responsive behavior, which was verified by zeta masters instrument and dynamic light scattering (DLS). Moreover, transmission electron microscopy (TEM) demonstrated the morphology of the micellar aggregates and the variation subjected to the lower pH and GSH, and the responsive mechanism was elaborated. Therefore, these results highlighted a facile synthesis of the environment-responsive polymers and provided a novel GSH/pH responsive material platform for further application.
2019, 30(12): 2043-2046
doi: 10.1016/j.cclet.2019.05.034
Abstract:
A facile approach has been adopted for coating cross-linked polystyrene (PS) shells on the surface of Fe3O4 magnetic clusters using reflux-precipitation polymerization (RPP). Treating the PS shell with chlorosulfonic acid yields magnetic composite particles with acid functionality. By adjusting the amount and proportion of monomers (styrene and divinylbenzene), the obtained magnetic composite particle solid acid (MPM-5S) exhibits a saturation magnetization value of 18 emu/g, a specific surface area of 243 m2/g and an acid density of 2.113 mmol/g. The MPM-5S magnetic solid acid catalyst was evaluated for esterification of oleic acid with methanol to prepare biodiesel. Under mild conditions, the conversion of oleic acid reached 91%, which was much higher than the catalytic activity of Amberlyst-15 and close to the catalytic activity of concentrated H2SO4. The solid acid catalyst can be recovered by magnetic separation and reused three times maintaining over 95% of its initial catalytic activity. Additionally, the solid acid can be used to catalyze the dehydration of fructose to 5-hydroxymethylfurfural.
A facile approach has been adopted for coating cross-linked polystyrene (PS) shells on the surface of Fe3O4 magnetic clusters using reflux-precipitation polymerization (RPP). Treating the PS shell with chlorosulfonic acid yields magnetic composite particles with acid functionality. By adjusting the amount and proportion of monomers (styrene and divinylbenzene), the obtained magnetic composite particle solid acid (MPM-5S) exhibits a saturation magnetization value of 18 emu/g, a specific surface area of 243 m2/g and an acid density of 2.113 mmol/g. The MPM-5S magnetic solid acid catalyst was evaluated for esterification of oleic acid with methanol to prepare biodiesel. Under mild conditions, the conversion of oleic acid reached 91%, which was much higher than the catalytic activity of Amberlyst-15 and close to the catalytic activity of concentrated H2SO4. The solid acid catalyst can be recovered by magnetic separation and reused three times maintaining over 95% of its initial catalytic activity. Additionally, the solid acid can be used to catalyze the dehydration of fructose to 5-hydroxymethylfurfural.
2019, 30(12): 2047-2050
doi: 10.1016/j.cclet.2019.06.010
Abstract:
Pathogenic bacterial contaminations in water cause serious or even lethal threats. Strategies that effectively kill bacteria without causing environmental contamination are urgently needed in a wide range of applications. We prepared recyclable antimicrobial magnetic nanoparticles, Fe3O4@P(St-co-AcQAC), through surfactant-free seeded emulsion polymerization involving a polymerizable, hydrophobic quaternary ammonium compound (QAC). Fe3O4 particles were first synthesized by a solvothermal reaction, followed by functionalization with a methacrylic silane (MPS), and then copolymerized with a QAC-containing acrylic monomer (AcQAC), leading to Fe3O4@P(St-co-AcQAC) nanoparticles. As confirmed by antibacterial assays, these Fe3O4@P(St-co-AcQAC) nanoparticles exhibited strong antimicrobial action against both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli, without leaching out any bactericidal agent. An additional benefit of antimicrobial magnetic particles is that they can be easily recycled while maintaining excellent antimicrobial efficacy.
Pathogenic bacterial contaminations in water cause serious or even lethal threats. Strategies that effectively kill bacteria without causing environmental contamination are urgently needed in a wide range of applications. We prepared recyclable antimicrobial magnetic nanoparticles, Fe3O4@P(St-co-AcQAC), through surfactant-free seeded emulsion polymerization involving a polymerizable, hydrophobic quaternary ammonium compound (QAC). Fe3O4 particles were first synthesized by a solvothermal reaction, followed by functionalization with a methacrylic silane (MPS), and then copolymerized with a QAC-containing acrylic monomer (AcQAC), leading to Fe3O4@P(St-co-AcQAC) nanoparticles. As confirmed by antibacterial assays, these Fe3O4@P(St-co-AcQAC) nanoparticles exhibited strong antimicrobial action against both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli, without leaching out any bactericidal agent. An additional benefit of antimicrobial magnetic particles is that they can be easily recycled while maintaining excellent antimicrobial efficacy.
2019, 30(12): 2157-2159
doi: 10.1016/j.cclet.2019.04.044
Abstract:
Oxidative stress results in various pathologies and as consequence antioxidant agents have attracted uninterrupted attention. In this paper, a novel series of indole-3-carboxamide derivatives (6a-6l) were designed and synthesized based on the melatonin structure as novel antioxidants. All of them were evaluated for the antioxidant activities in vitro against human neuroblastoma SH-SY5Y cell line using H2O2 radical scavenging assay. The target compounds 6a, 6f and 6i indicated better activities than the positive control, ascorbic acid, and 6a exhibited the best antioxidant activity. In addition, the structureactivity relationships of the target compounds were also preliminarily summarized based on the obtained experimental data.
Oxidative stress results in various pathologies and as consequence antioxidant agents have attracted uninterrupted attention. In this paper, a novel series of indole-3-carboxamide derivatives (6a-6l) were designed and synthesized based on the melatonin structure as novel antioxidants. All of them were evaluated for the antioxidant activities in vitro against human neuroblastoma SH-SY5Y cell line using H2O2 radical scavenging assay. The target compounds 6a, 6f and 6i indicated better activities than the positive control, ascorbic acid, and 6a exhibited the best antioxidant activity. In addition, the structureactivity relationships of the target compounds were also preliminarily summarized based on the obtained experimental data.
2019, 30(12): 2160-2162
doi: 10.1016/j.cclet.2019.04.072
Abstract:
Acetohydroxyacid synthase (AHAS) was considered as a promising target for antifungal agents. Herein, three series of novel sulfonylureas (SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy. The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities. Based on the preliminary fungicidal activities, a CoMFA model was constructed and the 3D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities. In order to study interaction mechanism, 10k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities. It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS. Thus, the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphytopathogenic fungal agents.
Acetohydroxyacid synthase (AHAS) was considered as a promising target for antifungal agents. Herein, three series of novel sulfonylureas (SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy. The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities. Based on the preliminary fungicidal activities, a CoMFA model was constructed and the 3D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities. In order to study interaction mechanism, 10k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities. It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS. Thus, the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphytopathogenic fungal agents.
2019, 30(12): 2163-2168
doi: 10.1016/j.cclet.2019.06.004
Abstract:
Reductive immobilization of radioactive pertechnetate (99TcO4-) in simulated groundwater was studied by prepared carboxymethyl cellulose (CMC) and starch stabilized zero valent iron nanoparticles (nZVI), and long-term remobilization of reduced Tc was also evaluated under anoxic and oxic conditions. The stabilized nZVI can effectively reduce soluble 99Tc(Ⅶ) to insoluble 99Tc(Ⅳ), and they can be easily delivered into a contaminated groundwater zone and facilitate in situ remediation. In this study, CMC-stabilized nZVI showed higher reactivity than that using starch as the stabilizer. Batch experiments indicated that more than 99% of 99Tc(Ⅶ) (C0=12 mg/mL) was reduced and removed from groundwater by CMC-stabilized nZVI with a CMC content of 0.2% (w/w) at a broad pH of 5-8. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses further confirmed that 99Tc(Ⅶ)O4- transformed into 99Tc(Ⅳ)O2 (s). The presence of bicarbonate exhibited insignificant effect on Tc immobilization, while humic acid (HA) inhibited reaction mainly due to retardation on electron transfer and formation of Tc(Ⅳ)-HA complexes. More interesting, the immobilized Tc(Ⅳ) remained insoluble even after 120 d under anoxic condition, while only~21% was remobilized when exposed to air. Therefore, biomacromolecules stabilized nZVI nanoparticles could be a viable alternative for in situ remediation of radioactive contamination in groundwater.
Reductive immobilization of radioactive pertechnetate (99TcO4-) in simulated groundwater was studied by prepared carboxymethyl cellulose (CMC) and starch stabilized zero valent iron nanoparticles (nZVI), and long-term remobilization of reduced Tc was also evaluated under anoxic and oxic conditions. The stabilized nZVI can effectively reduce soluble 99Tc(Ⅶ) to insoluble 99Tc(Ⅳ), and they can be easily delivered into a contaminated groundwater zone and facilitate in situ remediation. In this study, CMC-stabilized nZVI showed higher reactivity than that using starch as the stabilizer. Batch experiments indicated that more than 99% of 99Tc(Ⅶ) (C0=12 mg/mL) was reduced and removed from groundwater by CMC-stabilized nZVI with a CMC content of 0.2% (w/w) at a broad pH of 5-8. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses further confirmed that 99Tc(Ⅶ)O4- transformed into 99Tc(Ⅳ)O2 (s). The presence of bicarbonate exhibited insignificant effect on Tc immobilization, while humic acid (HA) inhibited reaction mainly due to retardation on electron transfer and formation of Tc(Ⅳ)-HA complexes. More interesting, the immobilized Tc(Ⅳ) remained insoluble even after 120 d under anoxic condition, while only~21% was remobilized when exposed to air. Therefore, biomacromolecules stabilized nZVI nanoparticles could be a viable alternative for in situ remediation of radioactive contamination in groundwater.
2019, 30(12): 2169-2172
doi: 10.1016/j.cclet.2019.06.023
Abstract:
A novel 1, 8-naphthalimide-based OFF-ON type fluorogenic sydnone (Naph-Syd) is designed as bioorthogonal probe for imaging. Sydnone moiety efficiently quenches the native fluorescence of 1, 8-naphthalimide, which can be restored with the enhancement of about 300-fold, after reacting with strained cyclooctynes to form pyrazole products (Naph-Pyr). The second-order rate constant of this bioorthogonal cycloaddition can be up to 2.5 L mol-1 s-1, which benefits imaging of biomolecules at low concentrations in cellular environment.
A novel 1, 8-naphthalimide-based OFF-ON type fluorogenic sydnone (Naph-Syd) is designed as bioorthogonal probe for imaging. Sydnone moiety efficiently quenches the native fluorescence of 1, 8-naphthalimide, which can be restored with the enhancement of about 300-fold, after reacting with strained cyclooctynes to form pyrazole products (Naph-Pyr). The second-order rate constant of this bioorthogonal cycloaddition can be up to 2.5 L mol-1 s-1, which benefits imaging of biomolecules at low concentrations in cellular environment.
2019, 30(12): 2173-2176
doi: 10.1016/j.cclet.2019.06.045
Abstract:
The obvious enhancement effect of magnetic nanoparticles (MNPs) introduced in Cr/Co/Cr/Au substrate on the pulsed magnetic field-modulated surface plasmon coupled emission (SPCE) was investigated, and the observed enhancement factor was 4 comparing with the magnetic field modulated SPCE without MNPs. This is the new observation for the magnetic field modulated SPCE, and this method was designed as a biosensor, which to our knowledge, is the first application of magnetic field-modulated SPCE in biosensing and detection field. This strategy is a universal approach to increase the fluorescence signal and helps to build the new SPCE based stimulus-response system.
The obvious enhancement effect of magnetic nanoparticles (MNPs) introduced in Cr/Co/Cr/Au substrate on the pulsed magnetic field-modulated surface plasmon coupled emission (SPCE) was investigated, and the observed enhancement factor was 4 comparing with the magnetic field modulated SPCE without MNPs. This is the new observation for the magnetic field modulated SPCE, and this method was designed as a biosensor, which to our knowledge, is the first application of magnetic field-modulated SPCE in biosensing and detection field. This strategy is a universal approach to increase the fluorescence signal and helps to build the new SPCE based stimulus-response system.
2019, 30(12): 2177-2180
doi: 10.1016/j.cclet.2019.07.050
Abstract:
In this study, a novel class of niobium (Nb) doped titanate nanoflakes (TNFs) are fabricated through a onestep hydrothermal method. Nb doping affects the curving of titanate nanosheet, leading to the formation of nanoflake structure. In addition, Nb5+ filled in the interlayers of[TiO6] alters the light adsorption property of pristine titanate. The band gap of Nb-TNFs is narrowed to 2.85 eV, while neat titanate nanotubes (TNTs) is 3.4 eV. The enhanced visible light adsorption significantly enhances the visible-lightdriven activity of Nb-TNFs for ibuprofen (IBP) degradation. The pseudo-first order kinetics constant for Nb-TNFs is calculated to be 1.04 h-1, while no obvious removal is observed for TNTs. Photo-generated holes (h+) and hydroxyl radicals (·OH) are responsible for IBP degradation. The photocatalytic activity of Nb-TNFs depends on pH condition, and the optimal pH value is found to be 5. In addition, Nb-TNFs exhibited superior photo-stability during the reuse cycles. The results demonstrated Nb-TNFs are very promising in photocatalytic water purification.
In this study, a novel class of niobium (Nb) doped titanate nanoflakes (TNFs) are fabricated through a onestep hydrothermal method. Nb doping affects the curving of titanate nanosheet, leading to the formation of nanoflake structure. In addition, Nb5+ filled in the interlayers of[TiO6] alters the light adsorption property of pristine titanate. The band gap of Nb-TNFs is narrowed to 2.85 eV, while neat titanate nanotubes (TNTs) is 3.4 eV. The enhanced visible light adsorption significantly enhances the visible-lightdriven activity of Nb-TNFs for ibuprofen (IBP) degradation. The pseudo-first order kinetics constant for Nb-TNFs is calculated to be 1.04 h-1, while no obvious removal is observed for TNTs. Photo-generated holes (h+) and hydroxyl radicals (·OH) are responsible for IBP degradation. The photocatalytic activity of Nb-TNFs depends on pH condition, and the optimal pH value is found to be 5. In addition, Nb-TNFs exhibited superior photo-stability during the reuse cycles. The results demonstrated Nb-TNFs are very promising in photocatalytic water purification.
2019, 30(12): 2181-2185
doi: 10.1016/j.cclet.2019.06.046
Abstract:
Investigations of glycosylated proteins or peptides and their related biological pathways provide new possibilities for illuminating the physiological and pathological mechanisms of glycosylation modification. However, open-ended and in-depth analysis of glycoproteomics is usually subjected to the low-abundance of glycopeptides, heterogeneous glycans, and a variety of interference molecules. In order to alleviate the influence of these obstacles, effective preconcentration of glycopeptides are indispensable. Here, we employed a hydrophilic interaction liquid chromatography (HILIC)-based method to universally capture glycopeptides. Glutathione modified magnetic nanoparticles (Fe3O4@AuGSH) were synthesized through a simple process and exploited to enrich glycopeptides from complex samples. The prepared materials showed excellent ability to trap glycopeptides from standard glycoproteins digests, low detection limit (10 fmol/μL), and good selectivity (HRP:BSA=1:100). These results indicated that glutathione-based magnetic nanoparticles synthesized in this work had great potential for glycopeptides enrichment.
Investigations of glycosylated proteins or peptides and their related biological pathways provide new possibilities for illuminating the physiological and pathological mechanisms of glycosylation modification. However, open-ended and in-depth analysis of glycoproteomics is usually subjected to the low-abundance of glycopeptides, heterogeneous glycans, and a variety of interference molecules. In order to alleviate the influence of these obstacles, effective preconcentration of glycopeptides are indispensable. Here, we employed a hydrophilic interaction liquid chromatography (HILIC)-based method to universally capture glycopeptides. Glutathione modified magnetic nanoparticles (Fe3O4@AuGSH) were synthesized through a simple process and exploited to enrich glycopeptides from complex samples. The prepared materials showed excellent ability to trap glycopeptides from standard glycoproteins digests, low detection limit (10 fmol/μL), and good selectivity (HRP:BSA=1:100). These results indicated that glutathione-based magnetic nanoparticles synthesized in this work had great potential for glycopeptides enrichment.
2019, 30(12): 2186-2190
doi: 10.1016/j.cclet.2019.08.014
Abstract:
Graphitic carbon nitride (g-C3N4), as a visible-light-active organic semiconductor, has attracted growing attentions in photocatalysis and photoluminescence-based biosensing. Here, we demonstrated the intrinsic photooxidase activity of g-C3N4 and then surface molecular imprinting on g-C3N4 nanozymes was achieved for improved biosensing. Upon blue LED irradiation, the g-C3N4 exhibited superior enzymatic activity for oxidation of chromogenic substrate like 3, 3', 5, 5'-tetramethylbenzidine (TMB) without destructive H2O2. The oxidation was mainly ascribed to ·O2- that was generated during light irradiation. The surface molecular imprinting on g-C3N4 can lead to an over 1000-fold alleviation in matrix-interference from serum samples, 4-fold improved enzymatic activity as well as enhanced substrate specificity comparing with bare g-C3N4 during colorimetric sensing. Also, the MIP-g-C3N4 possesses a high affinity to TMB with a Km value of only 22 μmol/L, much lower than other comment nanozymes like AuNPs, Fe3O4 NPs, etc. It was successfully applied for detection of cysteine in serum sample with satisfactory recoveries.
Graphitic carbon nitride (g-C3N4), as a visible-light-active organic semiconductor, has attracted growing attentions in photocatalysis and photoluminescence-based biosensing. Here, we demonstrated the intrinsic photooxidase activity of g-C3N4 and then surface molecular imprinting on g-C3N4 nanozymes was achieved for improved biosensing. Upon blue LED irradiation, the g-C3N4 exhibited superior enzymatic activity for oxidation of chromogenic substrate like 3, 3', 5, 5'-tetramethylbenzidine (TMB) without destructive H2O2. The oxidation was mainly ascribed to ·O2- that was generated during light irradiation. The surface molecular imprinting on g-C3N4 can lead to an over 1000-fold alleviation in matrix-interference from serum samples, 4-fold improved enzymatic activity as well as enhanced substrate specificity comparing with bare g-C3N4 during colorimetric sensing. Also, the MIP-g-C3N4 possesses a high affinity to TMB with a Km value of only 22 μmol/L, much lower than other comment nanozymes like AuNPs, Fe3O4 NPs, etc. It was successfully applied for detection of cysteine in serum sample with satisfactory recoveries.
2019, 30(12): 2191-2195
doi: 10.1016/j.cclet.2019.09.031
Abstract:
Hollow microsphere structure cobalt hydroxide (h-Co(OH)2) was synthesized via an optimized solvothermal-hydrothermal process and applied to activate peroxymonosulfate (PMS) for degradation of a typical pharmaceutically active compound, ibuprofen (IBP). The material characterizations confirmed the presence of the microscale hollow spheres with thin nanosheets shell in h-Co(OH)2, and the crystalline phase was assigned to α-Co(OH)2. h-Co(OH)2 could efficiently activate PMS for radicals production, and 98.6% of IBP was degraded at 10 min. The activation of PMS by h-Co(OH)2 was a pHindependent process, and pH 7 was the optimum condition for the activation-degradation system. Scavenger quenching test indicated that the sulfate radical (SO4·-) was the primary reactive oxygen species for IBP degradation, which contributed to 75.7%. Fukui index (f-) based on density functional theory (DFT) calculation predicted the active sites of IBP molecule for SO4·- attack, and then IBP degradation pathway was proposed by means of intermediates identification and theoretical calculation. The developed hollow Co(OH)2 used to efficiently activate PMS is promising and innovative alternative for organic contaminants removal from water and wastewater.
Hollow microsphere structure cobalt hydroxide (h-Co(OH)2) was synthesized via an optimized solvothermal-hydrothermal process and applied to activate peroxymonosulfate (PMS) for degradation of a typical pharmaceutically active compound, ibuprofen (IBP). The material characterizations confirmed the presence of the microscale hollow spheres with thin nanosheets shell in h-Co(OH)2, and the crystalline phase was assigned to α-Co(OH)2. h-Co(OH)2 could efficiently activate PMS for radicals production, and 98.6% of IBP was degraded at 10 min. The activation of PMS by h-Co(OH)2 was a pHindependent process, and pH 7 was the optimum condition for the activation-degradation system. Scavenger quenching test indicated that the sulfate radical (SO4·-) was the primary reactive oxygen species for IBP degradation, which contributed to 75.7%. Fukui index (f-) based on density functional theory (DFT) calculation predicted the active sites of IBP molecule for SO4·- attack, and then IBP degradation pathway was proposed by means of intermediates identification and theoretical calculation. The developed hollow Co(OH)2 used to efficiently activate PMS is promising and innovative alternative for organic contaminants removal from water and wastewater.
2019, 30(12): 2196-2200
doi: 10.1016/j.cclet.2019.09.035
Abstract:
A novel Fe/amine modified chitosan composite (Fe/N-CS) was facilely synthesized and showed higher affinity to both Zn(Ⅱ) and cefazolin (CEF) than its precursors. Synergistic co-adsorption of them by Fe/NCS was observed in varied conditions. The adsorption amount maximally increased by 100.1% for Zn and 68.2% for CEF in bi-solute systems. The initial adsorption rate of Zn(Ⅱ) also improved with CEF. The increasing temperature facilitated coadsorption. The results of the preloading tests, FTIR/XPS characterizations and DFT calculations suggested that (1) both polyamines and Fe sites participated in the adsorption of Zn(Ⅱ) and CEF, (2) Zn(Ⅱ) could serve as a new efficient site for CEF, forming[amine-Zn-CEF]/[FeOH-Zn-CEF] ternary complexes, and (3) the co-presence of CEF shielded the electrostatic repulsion between protonated amines and Zn(Ⅱ), contributing to the enhancement of Zn(Ⅱ) adsorption. Further, the ion strength exerted positive and negative influences on the adsorption of Zn(Ⅱ) and CEF, respectively. Additionally, CEF and Zn(Ⅱ) were successively recovered by 0.1 mol/L NaOH followed by 2 mmol/L HCl. Fe/N-CS could be stably reused five times. The findings imply that Fe/N-CS is promising for the highly efficient co-removal of concurrent heavy metals and antibiotics.
A novel Fe/amine modified chitosan composite (Fe/N-CS) was facilely synthesized and showed higher affinity to both Zn(Ⅱ) and cefazolin (CEF) than its precursors. Synergistic co-adsorption of them by Fe/NCS was observed in varied conditions. The adsorption amount maximally increased by 100.1% for Zn and 68.2% for CEF in bi-solute systems. The initial adsorption rate of Zn(Ⅱ) also improved with CEF. The increasing temperature facilitated coadsorption. The results of the preloading tests, FTIR/XPS characterizations and DFT calculations suggested that (1) both polyamines and Fe sites participated in the adsorption of Zn(Ⅱ) and CEF, (2) Zn(Ⅱ) could serve as a new efficient site for CEF, forming[amine-Zn-CEF]/[FeOH-Zn-CEF] ternary complexes, and (3) the co-presence of CEF shielded the electrostatic repulsion between protonated amines and Zn(Ⅱ), contributing to the enhancement of Zn(Ⅱ) adsorption. Further, the ion strength exerted positive and negative influences on the adsorption of Zn(Ⅱ) and CEF, respectively. Additionally, CEF and Zn(Ⅱ) were successively recovered by 0.1 mol/L NaOH followed by 2 mmol/L HCl. Fe/N-CS could be stably reused five times. The findings imply that Fe/N-CS is promising for the highly efficient co-removal of concurrent heavy metals and antibiotics.
2019, 30(12): 2201-2204
doi: 10.1016/j.cclet.2019.10.032
Abstract:
Canine parvovirus type 2 (CPV-2) infection is the most lethal disease of dogs with higher mortality in puppies worldwide. In today's world, dogs are an integral part of our communities as well as dogs breeding and rearing has become a lucrative business. Therefore, a fast, accurate, portable, and costeffective CPV-2 detection method with the ability for on-site detection is highly desired. In this study, we for the first time proposed a nanosystem for CPV-2 DNA detection with RNA-guided RNA endonuclease Cas13a, which upon activation results in collateral RNA degradation. We expressed LwCas13a in prokaryotic expression system and purified it through nickel column. Activity of Cas13a was verified by RNA-bound fluorescent group while using a quenched fluorescent probe as signals. Further Cas13a was combined with Recombinase polymerase amplification (RPA) and T7 transcription to establish molecular detection system termed specific high-sensitivity enzymatic reporter un-locking (SHERLOCK) for sensitive detection of CPV-2 DNA. This nanosystem can detect 100 amol/L CPV-2 DNA within 30 min. The proposed nanosystem exhibited high specificity when tested for CPV-2 and other dog viruses. This CRISPR-Cas13a mediated sensitive detection approach can be of formidable advantage during CPV-2 outbreaks because it is time-efficient, less laborious and does not involve the use of sophisticated instruments.
Canine parvovirus type 2 (CPV-2) infection is the most lethal disease of dogs with higher mortality in puppies worldwide. In today's world, dogs are an integral part of our communities as well as dogs breeding and rearing has become a lucrative business. Therefore, a fast, accurate, portable, and costeffective CPV-2 detection method with the ability for on-site detection is highly desired. In this study, we for the first time proposed a nanosystem for CPV-2 DNA detection with RNA-guided RNA endonuclease Cas13a, which upon activation results in collateral RNA degradation. We expressed LwCas13a in prokaryotic expression system and purified it through nickel column. Activity of Cas13a was verified by RNA-bound fluorescent group while using a quenched fluorescent probe as signals. Further Cas13a was combined with Recombinase polymerase amplification (RPA) and T7 transcription to establish molecular detection system termed specific high-sensitivity enzymatic reporter un-locking (SHERLOCK) for sensitive detection of CPV-2 DNA. This nanosystem can detect 100 amol/L CPV-2 DNA within 30 min. The proposed nanosystem exhibited high specificity when tested for CPV-2 and other dog viruses. This CRISPR-Cas13a mediated sensitive detection approach can be of formidable advantage during CPV-2 outbreaks because it is time-efficient, less laborious and does not involve the use of sophisticated instruments.
2019, 30(12): 2205-2210
doi: 10.1016/j.cclet.2019.09.052
Abstract:
There is a relatively low efficiency of Fe(Ⅲ)/Fe(Ⅱ) conversion cycle and H2O2 decomposition (< 30%) in conventional Fenton process, which further results in a low production efficiency of ·OH and seriously restricts the application of Fenton. Herein, we report that the commercial MoO2 can be used as the cocatalyst in Fenton process to dramatically accelerate the oxidation of Lissamine rhodamine B (L-RhB), where the efficiency of Fe(Ⅲ)/Fe(Ⅱ) cycling is greatly enhanced in the Fenton reaction meanwhile. And the L-RhB solution could be degraded nearly 100% in 1 min in the MoO2 cocatalytic Fenton system under the optimal reaction condition, which is apparently better than that of the conventional Fenton system (~50%). Different from the conventional Fenton reaction where the ·OH plays an important role in the oxidation process, it shows that 1O2 contributes most in the MoO2 cocatalytic Fenton reaction. However, it is found that the exposed Mo4+ active sites on the surface of MoO2 powders can greatly promote the rate-limiting step of Fe3+/Fe2+ cycle conversion, thus minimizing the dosage of H2O2 (0.400 mmol/L) and Fe2+ (0.105 mmol/L). Interestingly, the MoO2 cocatalytic Fenton system also exhibits a good ability for reducing Cr(Ⅵ) ions, where the reduction ability for Cr(Ⅵ) reaches almost 100% within 2 h. In short, this work shows a new discovery for MoO2 cocatalytic advanced oxidation processes (AOPs), which devotes a lot to the practical water remediation application.
There is a relatively low efficiency of Fe(Ⅲ)/Fe(Ⅱ) conversion cycle and H2O2 decomposition (< 30%) in conventional Fenton process, which further results in a low production efficiency of ·OH and seriously restricts the application of Fenton. Herein, we report that the commercial MoO2 can be used as the cocatalyst in Fenton process to dramatically accelerate the oxidation of Lissamine rhodamine B (L-RhB), where the efficiency of Fe(Ⅲ)/Fe(Ⅱ) cycling is greatly enhanced in the Fenton reaction meanwhile. And the L-RhB solution could be degraded nearly 100% in 1 min in the MoO2 cocatalytic Fenton system under the optimal reaction condition, which is apparently better than that of the conventional Fenton system (~50%). Different from the conventional Fenton reaction where the ·OH plays an important role in the oxidation process, it shows that 1O2 contributes most in the MoO2 cocatalytic Fenton reaction. However, it is found that the exposed Mo4+ active sites on the surface of MoO2 powders can greatly promote the rate-limiting step of Fe3+/Fe2+ cycle conversion, thus minimizing the dosage of H2O2 (0.400 mmol/L) and Fe2+ (0.105 mmol/L). Interestingly, the MoO2 cocatalytic Fenton system also exhibits a good ability for reducing Cr(Ⅵ) ions, where the reduction ability for Cr(Ⅵ) reaches almost 100% within 2 h. In short, this work shows a new discovery for MoO2 cocatalytic advanced oxidation processes (AOPs), which devotes a lot to the practical water remediation application.
2019, 30(12): 2211-2215
doi: 10.1016/j.cclet.2019.05.020
Abstract:
An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd2+ and Pb2+. The experimental results showed that the electrochemical performance of nano PPCPE is evidently better than both glassy carbon electrode(GCE) and pure carbon paste electrode (CPE). Then the prepared nano-PPCPE was applied to detect Cd2+ and Pb2+ in standard solution, the results showed that the electrodes can quantitatively detect trace Cd2+ and Pb2+, which has great significance in electrochemical analysis and detection. The linear ranges between the target ions concentration and the DPASV current were from 0.1-3.0 μmol/L, 0.05-4.0 μmol/L for Cd2+ and Pb2+, respectively. And the detection limits were 0.0780 μmol/L and 0.0292 μmol/L, respectively. Moreover, the preparation of the nano-PPCPE is cheap, simple and has important practical value.
An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd2+ and Pb2+. The experimental results showed that the electrochemical performance of nano PPCPE is evidently better than both glassy carbon electrode(GCE) and pure carbon paste electrode (CPE). Then the prepared nano-PPCPE was applied to detect Cd2+ and Pb2+ in standard solution, the results showed that the electrodes can quantitatively detect trace Cd2+ and Pb2+, which has great significance in electrochemical analysis and detection. The linear ranges between the target ions concentration and the DPASV current were from 0.1-3.0 μmol/L, 0.05-4.0 μmol/L for Cd2+ and Pb2+, respectively. And the detection limits were 0.0780 μmol/L and 0.0292 μmol/L, respectively. Moreover, the preparation of the nano-PPCPE is cheap, simple and has important practical value.
2019, 30(12): 2216-2220
doi: 10.1016/j.cclet.2019.05.039
Abstract:
Recently, heterogeneous activation of peroxymonosulfate (PMS) to oxidatively degrade organic pollutants has been a hotspot. In the present work, copper ferrite-graphite oxide hybrid (CuFe2O4@GO) was prepared and used as catalyst to activate PMS for degradation of methylene blue (MB) in aqueous solution. A high degradation efficiency (93.3%) was achieved at the experimental conditions of 20 mg/L MB, 200 mg/L CuFe2O4@GO, 0.8 mmol/L PMS, and 25℃ temperature. Moreover, CuFe2O4@GO showed an excellent reusability and stability. The effects of various operational parameters including pollutant type, solution pH, catalyst dosage, PMS dosage, pollutant concentration, temperature, natural organic matter (NOM), and inorganic anions on the catalytic degradation process were comprehensively investigated and elucidated. The further mechanistic study revealed the Cu(Ⅱ)/Cu(Ⅰ) redox couple on CuFe2O4@GO played the dominant role in PMS activation, where both hydroxyl and sulfate radicals were generated and proceeded the degradation of pollutants. In general, CuFe2O4@GO is a promising heterocatalyst for PMS-based advanced oxidation processes (AOPs) in wastewater treatment.
Recently, heterogeneous activation of peroxymonosulfate (PMS) to oxidatively degrade organic pollutants has been a hotspot. In the present work, copper ferrite-graphite oxide hybrid (CuFe2O4@GO) was prepared and used as catalyst to activate PMS for degradation of methylene blue (MB) in aqueous solution. A high degradation efficiency (93.3%) was achieved at the experimental conditions of 20 mg/L MB, 200 mg/L CuFe2O4@GO, 0.8 mmol/L PMS, and 25℃ temperature. Moreover, CuFe2O4@GO showed an excellent reusability and stability. The effects of various operational parameters including pollutant type, solution pH, catalyst dosage, PMS dosage, pollutant concentration, temperature, natural organic matter (NOM), and inorganic anions on the catalytic degradation process were comprehensively investigated and elucidated. The further mechanistic study revealed the Cu(Ⅱ)/Cu(Ⅰ) redox couple on CuFe2O4@GO played the dominant role in PMS activation, where both hydroxyl and sulfate radicals were generated and proceeded the degradation of pollutants. In general, CuFe2O4@GO is a promising heterocatalyst for PMS-based advanced oxidation processes (AOPs) in wastewater treatment.
2019, 30(12): 2221-2224
doi: 10.1016/j.cclet.2019.04.016
Abstract:
Biochars produced from crab shell (CSB), oak sawdust (OB), Jerusalem artichoke tuber (JAB) and sorghum grain (SB) displayed distinguishable adsorption-related characteristics, such as specific surface area (SSA), ash content and acidic oxygen-containing functional groups (AFGs), which linked to the biochar adsorption mechanisms of most pollutants. Herein, PO43-, Cd2+, and nitrobenzene (NB) were employed for adsorption by these biochars to elucidate the dominant factors for the adsorption. Adsorption performance of the three pollutants onto these four biochars varied considerably, as exemplified by the excellent adsorption of PO43- and Cd2+ onto CSB (225.3 and 116.0 mg/g, respectively) as compared with onto the other three biochars (4.2-37.1 mg/g for PO43- and 9.7-41.0 mg/g for Cd2+). OB displayed the best adsorption of NB (72.0 mg/g), followed by SB (39.5 mg/g), JAB (31.1 mg/g), and CSB (23.6 mg/g). The kinetics and isotherm adsorption assessments couple with material characterization suggested that the sorption of selected pollutants on biochars was attributed to the multiple mechanisms involved, including coprecipitation, chemical bonds, cation exchange, physical absorption, and complexation. Further path analysis suggested that AFGs and ash content in biochars were more important than SSA with regards to pollutant removal, especially, with ash playing a crucial role in the removal of Cd2+ and PO43-, and AFGs being mainly responsible for NB adsorption. These findings might offer guidance on the preparation or modification of biochar with a targeted function for pollutant removal through an understanding the dominant factors.
Biochars produced from crab shell (CSB), oak sawdust (OB), Jerusalem artichoke tuber (JAB) and sorghum grain (SB) displayed distinguishable adsorption-related characteristics, such as specific surface area (SSA), ash content and acidic oxygen-containing functional groups (AFGs), which linked to the biochar adsorption mechanisms of most pollutants. Herein, PO43-, Cd2+, and nitrobenzene (NB) were employed for adsorption by these biochars to elucidate the dominant factors for the adsorption. Adsorption performance of the three pollutants onto these four biochars varied considerably, as exemplified by the excellent adsorption of PO43- and Cd2+ onto CSB (225.3 and 116.0 mg/g, respectively) as compared with onto the other three biochars (4.2-37.1 mg/g for PO43- and 9.7-41.0 mg/g for Cd2+). OB displayed the best adsorption of NB (72.0 mg/g), followed by SB (39.5 mg/g), JAB (31.1 mg/g), and CSB (23.6 mg/g). The kinetics and isotherm adsorption assessments couple with material characterization suggested that the sorption of selected pollutants on biochars was attributed to the multiple mechanisms involved, including coprecipitation, chemical bonds, cation exchange, physical absorption, and complexation. Further path analysis suggested that AFGs and ash content in biochars were more important than SSA with regards to pollutant removal, especially, with ash playing a crucial role in the removal of Cd2+ and PO43-, and AFGs being mainly responsible for NB adsorption. These findings might offer guidance on the preparation or modification of biochar with a targeted function for pollutant removal through an understanding the dominant factors.
2019, 30(12): 2225-2230
doi: 10.1016/j.cclet.2019.07.058
Abstract:
Bismuth-based material has been broadly studied due to their potential applications in various areas, especially used as promising photocatalysts for the removal of persistent organic pollutants (POPs) and several approaches have been adopted to tailor their features. Herein, the bismuth-based photocatalysts (BiOCl, BiPO4, BiOPO4/BiOCl) were synthesized by hydrothermal method and advanced characterization techniques (XRD, SEM, EDS elemental mapping, Raman and UV-vis DRS) were employed to analyze their morphology, crystal structure, and purity of the prepared photocatalysts. These synthesized photocatalysts offered a praiseworthy activity as compared to commercial TiO2 (P25) for the degradation of model pollutant perfluorooctanoic acid (PFOA) under 254 nm UV light. It was interesting to observe that all synthesized photocatalysts show significant degradation of PFOA and their photocatalytic activity follows the order:bismuth-based catalysts > TiO2 (P25) > without catalyst. Bismuth-based catalysts degraded the PFOA by almost 99.99% within 45 min while this degradation efficiency was 66.05% with TiO2 under the same reaction condition. Our work shows that the bismuth-based photocatalysts are promising in PFOA treatment.
Bismuth-based material has been broadly studied due to their potential applications in various areas, especially used as promising photocatalysts for the removal of persistent organic pollutants (POPs) and several approaches have been adopted to tailor their features. Herein, the bismuth-based photocatalysts (BiOCl, BiPO4, BiOPO4/BiOCl) were synthesized by hydrothermal method and advanced characterization techniques (XRD, SEM, EDS elemental mapping, Raman and UV-vis DRS) were employed to analyze their morphology, crystal structure, and purity of the prepared photocatalysts. These synthesized photocatalysts offered a praiseworthy activity as compared to commercial TiO2 (P25) for the degradation of model pollutant perfluorooctanoic acid (PFOA) under 254 nm UV light. It was interesting to observe that all synthesized photocatalysts show significant degradation of PFOA and their photocatalytic activity follows the order:bismuth-based catalysts > TiO2 (P25) > without catalyst. Bismuth-based catalysts degraded the PFOA by almost 99.99% within 45 min while this degradation efficiency was 66.05% with TiO2 under the same reaction condition. Our work shows that the bismuth-based photocatalysts are promising in PFOA treatment.
2019, 30(12): 2231-2235
doi: 10.1016/j.cclet.2019.08.055
Abstract:
In this study, efficient sulfamethoxazole (SMX) degradation was demonstrated in a novel neutral Fered-Fenton like/oxalate (electro-Fe2+/PDS/Ox, Fered-FL/Ox) system adopting pre-anodized Ti@TiO2 cathode. Optimization of operational parameters was conducted and the whole reaction mechanism based on the critical solid-liquid interfacial reactions was explored. An efficient neutral heterogeneous-homogenous iron cycle would exist in the Fered-FL/Ox system, depending on the formation of specific C—O—Ti bonds through the inner sphere surface complex (ISSC) of Fe(C2O4)33-. It would induce ultrafast electron transfer from the cathode to the FeⅢ core, effectively accelerating the neutral Fenton-like reactions and complete mineralization of SMX with relative low dosage of ferrous catalyst and applied voltage. The result of this study is expected to supply a good alternative in treating complex neutral industrial wastewaters
In this study, efficient sulfamethoxazole (SMX) degradation was demonstrated in a novel neutral Fered-Fenton like/oxalate (electro-Fe2+/PDS/Ox, Fered-FL/Ox) system adopting pre-anodized Ti@TiO2 cathode. Optimization of operational parameters was conducted and the whole reaction mechanism based on the critical solid-liquid interfacial reactions was explored. An efficient neutral heterogeneous-homogenous iron cycle would exist in the Fered-FL/Ox system, depending on the formation of specific C—O—Ti bonds through the inner sphere surface complex (ISSC) of Fe(C2O4)33-. It would induce ultrafast electron transfer from the cathode to the FeⅢ core, effectively accelerating the neutral Fenton-like reactions and complete mineralization of SMX with relative low dosage of ferrous catalyst and applied voltage. The result of this study is expected to supply a good alternative in treating complex neutral industrial wastewaters
2019, 30(12): 2236-2240
doi: 10.1016/j.cclet.2019.07.041
Abstract:
Laboratory studies of HO2 uptake coefficients, γ(HO2), were conducted at room temperature using an aerosol flow tube coupled with a laser induced fluorescence (LIF) system. The measurement was conducted with atmospherically relevant HO2 concentrations (~1×109 molecule/cm3) at 51% RH. The measured γ(HO2) onto aqueous (NH4)2SO4 aerosol was 0.001 ±0.0007, which was consistent with the relatively low first-order loss rate of HO2 onto aqueous (NH4)2SO4 aerosol. The γ(HO2) was elevated with increase of Cu(Ⅱ) concentrations in aqueous (NH4)2SO4 aerosol. The threshold of Cu(Ⅱ) concentration was 10-3 mol/L for the dramatic increase of γ(HO2). It was found that γ(HO2) reached 0.1 when Cu(Ⅱ) concentration in aerosol was larger than 10-3 mol/L, suggesting that γ(HO2) is very sensitive to concentration of transition metal ions in aerosol.
Laboratory studies of HO2 uptake coefficients, γ(HO2), were conducted at room temperature using an aerosol flow tube coupled with a laser induced fluorescence (LIF) system. The measurement was conducted with atmospherically relevant HO2 concentrations (~1×109 molecule/cm3) at 51% RH. The measured γ(HO2) onto aqueous (NH4)2SO4 aerosol was 0.001 ±0.0007, which was consistent with the relatively low first-order loss rate of HO2 onto aqueous (NH4)2SO4 aerosol. The γ(HO2) was elevated with increase of Cu(Ⅱ) concentrations in aqueous (NH4)2SO4 aerosol. The threshold of Cu(Ⅱ) concentration was 10-3 mol/L for the dramatic increase of γ(HO2). It was found that γ(HO2) reached 0.1 when Cu(Ⅱ) concentration in aerosol was larger than 10-3 mol/L, suggesting that γ(HO2) is very sensitive to concentration of transition metal ions in aerosol.
2019, 30(12): 2241-2244
doi: 10.1016/j.cclet.2019.09.003
Abstract:
Dark formation of hydroxyl radical upon oxidation of reduced iron minerals plays an important role in the degradation and transformation of organic and inorganic pollutants. Herein, we compared the hydroxyl radical formation from various reduced iron minerals at different redox conditions. ·OH production was generally observed from the oxidation of reduced iron minerals, following the order:mackinawite (FeS) > reduced nontronite (iron-bearing smectite clay) > pyrite (FeS2) > siderite (FeCO3). Structural Fe2+ and dissolved O2 play critical roles in ·OH production from reduced iron minerals. ·OH production increases with decreasing pH, and Cl- has little effect on this process. More importantly, dissolved organic matter significantly enhances ·OH production, especially under O2 purging, highlighting the importance of this process in ambient environments. This sunlight-independent pathway in which ·OH forms during oxidation of reduced iron minerals is helpful for understanding the degradation and transformation of various inorganic and organic pollutants in the redox-fluctuation environments.
Dark formation of hydroxyl radical upon oxidation of reduced iron minerals plays an important role in the degradation and transformation of organic and inorganic pollutants. Herein, we compared the hydroxyl radical formation from various reduced iron minerals at different redox conditions. ·OH production was generally observed from the oxidation of reduced iron minerals, following the order:mackinawite (FeS) > reduced nontronite (iron-bearing smectite clay) > pyrite (FeS2) > siderite (FeCO3). Structural Fe2+ and dissolved O2 play critical roles in ·OH production from reduced iron minerals. ·OH production increases with decreasing pH, and Cl- has little effect on this process. More importantly, dissolved organic matter significantly enhances ·OH production, especially under O2 purging, highlighting the importance of this process in ambient environments. This sunlight-independent pathway in which ·OH forms during oxidation of reduced iron minerals is helpful for understanding the degradation and transformation of various inorganic and organic pollutants in the redox-fluctuation environments.
2019, 30(12): 2245-2248
doi: 10.1016/j.cclet.2019.05.046
Abstract:
A novel visible-light-driven Cu/rGO/MoS2 (CRM) ternary nanostructure as a photocatalyst with high catalytic activity towards environmental purification using solar energy was successfully synthesized through a facile solvothermal method. It was found that the nanoflower structure of MoS2 increased the number of its exposed edges. Meanwhile rGO as a catalytic substrate played a role of charge-carrier channel to improve the separation of holes and electrons, which originated from the band gap absorption of MoS2. The content of Cu in photocatalyst affected photocatalytic performance obviously. And the optimal 30% Cu/rGO/MoS2 possessed the highest photocatalytic performance, which could be attributed to the improved separation of charges and synergistic effects among Cu, rGO and MoS2. The removal efficiency of Rhodamine B (RhB) over CRM was up to 100% in 5 min. CRM as a photocatalyst maintained good reproducibility and stability during 3 times of the recycle experiments. These results indicate CRM is a promising photocatalyst for degrading organic pollutants in wastewater.
A novel visible-light-driven Cu/rGO/MoS2 (CRM) ternary nanostructure as a photocatalyst with high catalytic activity towards environmental purification using solar energy was successfully synthesized through a facile solvothermal method. It was found that the nanoflower structure of MoS2 increased the number of its exposed edges. Meanwhile rGO as a catalytic substrate played a role of charge-carrier channel to improve the separation of holes and electrons, which originated from the band gap absorption of MoS2. The content of Cu in photocatalyst affected photocatalytic performance obviously. And the optimal 30% Cu/rGO/MoS2 possessed the highest photocatalytic performance, which could be attributed to the improved separation of charges and synergistic effects among Cu, rGO and MoS2. The removal efficiency of Rhodamine B (RhB) over CRM was up to 100% in 5 min. CRM as a photocatalyst maintained good reproducibility and stability during 3 times of the recycle experiments. These results indicate CRM is a promising photocatalyst for degrading organic pollutants in wastewater.
2019, 30(12): 2249-2253
doi: 10.1016/j.cclet.2019.06.001
Abstract:
Alkaline-earth (Ae) metals have attracted a wealth of interdependent research from synthetic chemists. In Ae-catalyzed organometallic reactions, β-diketiminate is a typical ligand used to stabilize Ae catalysts by forming six-membered rings comprising Ae metals. Herein, studies focusing on the configuration of β-diketiminate-coordinated Ae compounds observed that the C—C and C—N bonds are homogeneous and unchanged. Furthermore, energetic studies observed that the formation of the Ae-incorporated sixmembered rings results in enhanced stability of > 20 kcal/mol. The nucleus-independent chemical shifts, anisotropy of the induced current density, and molecular orbital analyses demonstrated the nonaromaticity of the β-diketiminate-coordinated Ae compounds. The improved stability of these compounds can be explained by the delocalization of the π electrons derived from the β-diketiminate moiety.
Alkaline-earth (Ae) metals have attracted a wealth of interdependent research from synthetic chemists. In Ae-catalyzed organometallic reactions, β-diketiminate is a typical ligand used to stabilize Ae catalysts by forming six-membered rings comprising Ae metals. Herein, studies focusing on the configuration of β-diketiminate-coordinated Ae compounds observed that the C—C and C—N bonds are homogeneous and unchanged. Furthermore, energetic studies observed that the formation of the Ae-incorporated sixmembered rings results in enhanced stability of > 20 kcal/mol. The nucleus-independent chemical shifts, anisotropy of the induced current density, and molecular orbital analyses demonstrated the nonaromaticity of the β-diketiminate-coordinated Ae compounds. The improved stability of these compounds can be explained by the delocalization of the π electrons derived from the β-diketiminate moiety.
2019, 30(12): 2254-2258
doi: 10.1016/j.cclet.2019.05.040
Abstract:
Aromatic diimide dyes are an attractive class of redox-active organic molecules for lithium-ion batteries, whose battery performances (stabilities, conductivities and cyclicities) are strongly dependent on the sizes of their π-systems. However, due to the different Clar's structures possessed, three vertically π-extended aromatic diimides, namely, naphthalene diimide (two one-electron reductions), perylene diimide and terrylene diimide (two one-electron reductions), exhibit different electronic redox mechanisms when served as cathode materials in organic lithium-ion batteries. Herein, we have studied carefully the different electrochemical characteristics of the three aromatic diimides through experimental and theoretical calculations. Their battery present different shape of charge/discharge curves resulting from stability of their reduction state during charge/discharge process. Terrylene diimide shows better cycle and rate capacities than those of naphthalene diimide and perylene diimide, which could be attributed to the more energies released during terrylene diimide combining with lithium ions than those of other two diimides.
Aromatic diimide dyes are an attractive class of redox-active organic molecules for lithium-ion batteries, whose battery performances (stabilities, conductivities and cyclicities) are strongly dependent on the sizes of their π-systems. However, due to the different Clar's structures possessed, three vertically π-extended aromatic diimides, namely, naphthalene diimide (two one-electron reductions), perylene diimide and terrylene diimide (two one-electron reductions), exhibit different electronic redox mechanisms when served as cathode materials in organic lithium-ion batteries. Herein, we have studied carefully the different electrochemical characteristics of the three aromatic diimides through experimental and theoretical calculations. Their battery present different shape of charge/discharge curves resulting from stability of their reduction state during charge/discharge process. Terrylene diimide shows better cycle and rate capacities than those of naphthalene diimide and perylene diimide, which could be attributed to the more energies released during terrylene diimide combining with lithium ions than those of other two diimides.
2019, 30(12): 2259-2262
doi: 10.1016/j.cclet.2019.06.052
Abstract:
A simple and clean protocol for the synthesis of various alkyl and (hetero)aryl S-thiocarbamates was established. The usage of in situ generated hydroxide as both an oxygen source and hydrogen source as well as biomass-derived 2-methyltetrahydrofuran as a green reaction medium, the avoidance of phosphorus-containing reductant, and the generation of harmless water and nitrogen as the sideproducts have given the present method atom-economy and environmental friendliness.
A simple and clean protocol for the synthesis of various alkyl and (hetero)aryl S-thiocarbamates was established. The usage of in situ generated hydroxide as both an oxygen source and hydrogen source as well as biomass-derived 2-methyltetrahydrofuran as a green reaction medium, the avoidance of phosphorus-containing reductant, and the generation of harmless water and nitrogen as the sideproducts have given the present method atom-economy and environmental friendliness.
2019, 30(12): 2263-2265
doi: 10.1016/j.cclet.2019.07.018
Abstract:
Three novel small molecules with acceptor-donor-acceptor (A-D-A) configuration, SBDT1, SBDT2 and SBDT3, where 4, 8-bis(octyloxy)benzo[1, 2-b:4, 5-b']dithiophene (BDT) as the electron-donating core connecting to thiophene-substituted benzothiadiazole (BT) as electron-withdrawing are reported. The effects of fluorine atoms on the photophysical properties by introducing different fluorine atoms into the benzothiadiazole unit were investigated. These SBDTs exhibit good thermal stability, excellent panchromatic absorption in solution and film. SBDT2 and SBDT3 with fluorine-substituted BT possess a relatively deeper the highest occupied molecular orbital (HOMO). These A-D-A type molecules were treated as donor and PC71BM as acceptor in bulk heterojunction (BHJ) small-molecule organic solar cells (SMOSCs). Among them, device based on SBDT2 gave the best device performance with a PCE of 5.06% with Jsc of 10.56 mA/cm2, Voc of 0.85 V, fill factor (FF) of 56.4%. These studies indicate that proper incorporation of fluorine atoms is an effective way to increase the efficiency of organic solar cells.
Three novel small molecules with acceptor-donor-acceptor (A-D-A) configuration, SBDT1, SBDT2 and SBDT3, where 4, 8-bis(octyloxy)benzo[1, 2-b:4, 5-b']dithiophene (BDT) as the electron-donating core connecting to thiophene-substituted benzothiadiazole (BT) as electron-withdrawing are reported. The effects of fluorine atoms on the photophysical properties by introducing different fluorine atoms into the benzothiadiazole unit were investigated. These SBDTs exhibit good thermal stability, excellent panchromatic absorption in solution and film. SBDT2 and SBDT3 with fluorine-substituted BT possess a relatively deeper the highest occupied molecular orbital (HOMO). These A-D-A type molecules were treated as donor and PC71BM as acceptor in bulk heterojunction (BHJ) small-molecule organic solar cells (SMOSCs). Among them, device based on SBDT2 gave the best device performance with a PCE of 5.06% with Jsc of 10.56 mA/cm2, Voc of 0.85 V, fill factor (FF) of 56.4%. These studies indicate that proper incorporation of fluorine atoms is an effective way to increase the efficiency of organic solar cells.
2019, 30(12): 2266-2270
doi: 10.1016/j.cclet.2019.07.025
Abstract:
A series of novel six-coordinated terpyridine zinc complexes, containing ammonium salts and thymine fragment at the two terminals, have been designed and synthesized, which can function as highly sensitive visualized sensors for melamine detection via selective metallo-hydrogel formation. After fully characterization by various techniques, the complementary triple-hydrogen-bonding between the thymine fragment and melamine, as well as π-π stacking interactions may be responsible for the selective metallo-hydrogel formation. In light of the possible interference aroused by milk ingredients (proteins, peptides and amino acids) and legal/illegal additives (urine, sugars and vitamins), a series of control experiments are therefore involved. To our delight, this visual recognition is highly selective, no gelation was observed with the selected milk ingredients or additives. Remarkably, this new developed protocol enables convenient and highly selective visual recognition of melamine at a concentration as low as 10 ppm in raw milk without any tedious pretreatment.
A series of novel six-coordinated terpyridine zinc complexes, containing ammonium salts and thymine fragment at the two terminals, have been designed and synthesized, which can function as highly sensitive visualized sensors for melamine detection via selective metallo-hydrogel formation. After fully characterization by various techniques, the complementary triple-hydrogen-bonding between the thymine fragment and melamine, as well as π-π stacking interactions may be responsible for the selective metallo-hydrogel formation. In light of the possible interference aroused by milk ingredients (proteins, peptides and amino acids) and legal/illegal additives (urine, sugars and vitamins), a series of control experiments are therefore involved. To our delight, this visual recognition is highly selective, no gelation was observed with the selected milk ingredients or additives. Remarkably, this new developed protocol enables convenient and highly selective visual recognition of melamine at a concentration as low as 10 ppm in raw milk without any tedious pretreatment.
2019, 30(12): 2271-2273
doi: 10.1016/j.cclet.2019.07.027
Abstract:
Novel 5, 6, 5, 6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes (BOPYPYs) were obtained by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl)hydrazine in the presence of Et3N-BF3 Et2O for the first time. The absorption maxima of pyrazine-fused BOPYPY are obviously bathochromic shifts, in contrast to those of the reported BOPPY, indicating that the discrepant substitute groups between pyridine and pyrazine result in the remarkable wavelength difference. The new series of BOPYPYs possess high molar extinction coefficients, high fluorescence quantum yields, and larger Stokes shifts. A Knoevenagel reaction of BOPYPY with 4-dimethylaminobenzaldehyde smoothly produced the dye with the extension of π-conjugation. Dimethylamino-containing BOPYPY as a pH-responsive fluorescent sensor could detect pH value.
Novel 5, 6, 5, 6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes (BOPYPYs) were obtained by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl)hydrazine in the presence of Et3N-BF3 Et2O for the first time. The absorption maxima of pyrazine-fused BOPYPY are obviously bathochromic shifts, in contrast to those of the reported BOPPY, indicating that the discrepant substitute groups between pyridine and pyrazine result in the remarkable wavelength difference. The new series of BOPYPYs possess high molar extinction coefficients, high fluorescence quantum yields, and larger Stokes shifts. A Knoevenagel reaction of BOPYPY with 4-dimethylaminobenzaldehyde smoothly produced the dye with the extension of π-conjugation. Dimethylamino-containing BOPYPY as a pH-responsive fluorescent sensor could detect pH value.
2019, 30(12): 2274-2278
doi: 10.1016/j.cclet.2019.07.028
Abstract:
Defect engineering, especially oxygen vacancies (O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes. However, quantitative investigation of O-vacancies on CO2 electroreduction still remains rather ambiguous. Herein, a series of nanoporous tin oxide (SnOx) materials have been prepared by thermal treatment at various temperatures and reaction conditions. The annealing temperature dependent O-vacancies property of the SnOx was revealed and attributed to the balance tunning of the desorption of oxygen species and the continous oxidation of SnOx. The as-prepared nanoporous SnOx with 300℃ treatment was found to be highest O-vacant material and showed an impressive CO2RR activity and selectivity towards the conversion of CO2 into formic acid (up to 88.6%), and superior HCOOH incomplete current density to other samples. The ideal performance of the O-vacancies rich SnOx-300 material can be ascribed to the high delocalized electron density inducing much enhanced adsorption of CO2 with O binding and benefiting the subsequent reduction with high selectively forming of formic acid.
Defect engineering, especially oxygen vacancies (O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes. However, quantitative investigation of O-vacancies on CO2 electroreduction still remains rather ambiguous. Herein, a series of nanoporous tin oxide (SnOx) materials have been prepared by thermal treatment at various temperatures and reaction conditions. The annealing temperature dependent O-vacancies property of the SnOx was revealed and attributed to the balance tunning of the desorption of oxygen species and the continous oxidation of SnOx. The as-prepared nanoporous SnOx with 300℃ treatment was found to be highest O-vacant material and showed an impressive CO2RR activity and selectivity towards the conversion of CO2 into formic acid (up to 88.6%), and superior HCOOH incomplete current density to other samples. The ideal performance of the O-vacancies rich SnOx-300 material can be ascribed to the high delocalized electron density inducing much enhanced adsorption of CO2 with O binding and benefiting the subsequent reduction with high selectively forming of formic acid.
2019, 30(12): 2279-2281
doi: 10.1016/j.cclet.2019.07.060
Abstract:
A promoter-free Friedel-Crafts trifluoromethylthiolation of electron-rich arenes and heteroarenes with N-trifluoromethylthiosaccharin 5 using 2, 2, 2-trifluoroethanol (TFE) as the solvent was described. The reactions were conducted at 40℃ and a variety of common functional groups were compatible.
A promoter-free Friedel-Crafts trifluoromethylthiolation of electron-rich arenes and heteroarenes with N-trifluoromethylthiosaccharin 5 using 2, 2, 2-trifluoroethanol (TFE) as the solvent was described. The reactions were conducted at 40℃ and a variety of common functional groups were compatible.
2019, 30(12): 2282-2286
doi: 10.1016/j.cclet.2019.09.007
Abstract:
Enhancing the selectivity of imines for the oxidative self-coupling of primary amines was found to be challenging in the heterogeneous catalysis. Three different manganese oxides (M-3, M-4, M-5) were synthesized by controlling the calcination temperature using a simple template-free oxalate route. The prepared manganese oxides were systematically characterized using XRD, N2 sorption, SEM, TEM, XPS, H2-TPR techniques. M-4 gave 96.2% selectivity of imine at 100% conversion of benzylamine, which was far more superior than other existing protocols. Mn3+/Mn4+ ratio was found to affect the selectivity of the imines. The probable reaction pathway for amines oxidation catalyzed by manganese oxides was proposed for the first time.
Enhancing the selectivity of imines for the oxidative self-coupling of primary amines was found to be challenging in the heterogeneous catalysis. Three different manganese oxides (M-3, M-4, M-5) were synthesized by controlling the calcination temperature using a simple template-free oxalate route. The prepared manganese oxides were systematically characterized using XRD, N2 sorption, SEM, TEM, XPS, H2-TPR techniques. M-4 gave 96.2% selectivity of imine at 100% conversion of benzylamine, which was far more superior than other existing protocols. Mn3+/Mn4+ ratio was found to affect the selectivity of the imines. The probable reaction pathway for amines oxidation catalyzed by manganese oxides was proposed for the first time.
2019, 30(12): 2287-2290
doi: 10.1016/j.cclet.2019.08.002
Abstract:
An eco-friendly protocol for the synthesis of various 2-sulfonyl quinolines/pyridines through sulfonylation of heteroaromatic N-oxides with sodium sulfinates in water at ambient temperature under metal-and oxidant-free conditions has been developed. The mild reaction conditions, high reaction efficiency, operational simplicity, short reaction time and remarkable functional-group compatibility make the developed protocol very attractive for the preparation of 2-sulfonyl N-heteroaromatic compounds.
An eco-friendly protocol for the synthesis of various 2-sulfonyl quinolines/pyridines through sulfonylation of heteroaromatic N-oxides with sodium sulfinates in water at ambient temperature under metal-and oxidant-free conditions has been developed. The mild reaction conditions, high reaction efficiency, operational simplicity, short reaction time and remarkable functional-group compatibility make the developed protocol very attractive for the preparation of 2-sulfonyl N-heteroaromatic compounds.
2019, 30(12): 2291-2294
doi: 10.1016/j.cclet.2019.08.017
Abstract:
A biopolymer-inorganic hybrid system (MSN@PBLGF) is designed and fabricated from mesoporous silica nanoparticles (MSNs) and folic acid (FA)-terminated temperature-sensitive synthetic polypeptide, i.e., poly(γ-benzyl-L-glutamate) (PBLG) derivative, through a thiol-disulfide exchange reaction, where MSNs with high drug loading capacity serve as drug nanocarriers and the biocompatible PBLG biopolymer brushes installed on MSN surface through disulfide bonds endow the system with tumor-specific recognition ability and GSH/temperature dual-stimuli responsiveness. Controlled drug release experiments indicate that DOX can be tightly hosted in the system with limited premature release, but efficiently released in response to an increased concentration of GSH and/or an elevated temperature. Intracellular experiments demonstrate that the DOX-loaded MSN@PBLGF nanohybrid shows outstanding cellular uptake and cell-growth inhibition effects on human lung cancer cell line A549 in comparison with healthy human cells such as hepatocyte cells LO2.
A biopolymer-inorganic hybrid system (MSN@PBLGF) is designed and fabricated from mesoporous silica nanoparticles (MSNs) and folic acid (FA)-terminated temperature-sensitive synthetic polypeptide, i.e., poly(γ-benzyl-L-glutamate) (PBLG) derivative, through a thiol-disulfide exchange reaction, where MSNs with high drug loading capacity serve as drug nanocarriers and the biocompatible PBLG biopolymer brushes installed on MSN surface through disulfide bonds endow the system with tumor-specific recognition ability and GSH/temperature dual-stimuli responsiveness. Controlled drug release experiments indicate that DOX can be tightly hosted in the system with limited premature release, but efficiently released in response to an increased concentration of GSH and/or an elevated temperature. Intracellular experiments demonstrate that the DOX-loaded MSN@PBLGF nanohybrid shows outstanding cellular uptake and cell-growth inhibition effects on human lung cancer cell line A549 in comparison with healthy human cells such as hepatocyte cells LO2.
2019, 30(12): 2295-2298
doi: 10.1016/j.cclet.2019.09.040
Abstract:
The visible light promoted C-H sulfonylmethylation of imidazopyridines with easily accessible bromomethyl sulfones under mild reaction conditions was described. This protocol provides an effective and practical access to sulfonylmethylated imidazopyridines with good functional group tolerance. The desired products were provided in moderate to excellent yields for 50 examples at room temperature. The method could also be an attractive strategy to install a methyl group on imidazopyridines.
The visible light promoted C-H sulfonylmethylation of imidazopyridines with easily accessible bromomethyl sulfones under mild reaction conditions was described. This protocol provides an effective and practical access to sulfonylmethylated imidazopyridines with good functional group tolerance. The desired products were provided in moderate to excellent yields for 50 examples at room temperature. The method could also be an attractive strategy to install a methyl group on imidazopyridines.
2019, 30(12): 2299-2303
doi: 10.1016/j.cclet.2019.10.023
Abstract:
A fluorescent supramolecular polymer network with an excellent triple-stimuli responsive property based on metal-ligand coordination and host-guest interactions has been constructed from a terpyridine-monofunctionalized leaning tower[6]arene, a tetraphenylethylene AIEgen, and a bridging coordination ion (Zn2+). Addition of competitive binding agents, trifluoroacetic acid, and/or pillar[5]arene can break the metal coordination and/or host-guest inclusion complexation, and thermal heating can weaken the non-covalent interactions in the supramolecular polymer gel, all leading to the gel-to-sol transition.
A fluorescent supramolecular polymer network with an excellent triple-stimuli responsive property based on metal-ligand coordination and host-guest interactions has been constructed from a terpyridine-monofunctionalized leaning tower[6]arene, a tetraphenylethylene AIEgen, and a bridging coordination ion (Zn2+). Addition of competitive binding agents, trifluoroacetic acid, and/or pillar[5]arene can break the metal coordination and/or host-guest inclusion complexation, and thermal heating can weaken the non-covalent interactions in the supramolecular polymer gel, all leading to the gel-to-sol transition.
2019, 30(12): 2304-2308
doi: 10.1016/j.cclet.2019.10.031
Abstract:
An eco-friendly and economical route for the oxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-furandicarboxylic acid (FDCA) with atmospheric dioxygen as the sole oxidant under acid-, base-, metal-, and external initiator-free conditions in minimal solvent was reported. In the present reaction, the 1, 2-diethoxyethylane has a dual role:reaction medium and free-radical initiator. The FDCA easily crystallizes during the reaction and was simple purified via recrystallization to provide the pure FDCA.
An eco-friendly and economical route for the oxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-furandicarboxylic acid (FDCA) with atmospheric dioxygen as the sole oxidant under acid-, base-, metal-, and external initiator-free conditions in minimal solvent was reported. In the present reaction, the 1, 2-diethoxyethylane has a dual role:reaction medium and free-radical initiator. The FDCA easily crystallizes during the reaction and was simple purified via recrystallization to provide the pure FDCA.
2019, 30(12): 2309-2312
doi: 10.1016/j.cclet.2019.04.030
Abstract:
A stable hierarchical porous metal-organic framework PCN-56 with abundant Lewis acid sites (denoted as Defective-PCN-56) was synthesized by the low-temperature synthesis-induced defect formation method. The existence of mesopore in structure was confirmed by N2 sorption isotherm and the successful encapsulation of large dye molecules. The Defective-PCN-56 has higher loading capacity toward anti-cancer drug Doxo compared with that of "nearly ideal-crystal" (denoted as Ideal-PCN-56) synthesized at high temperature, showing potential application as drug carrier. The low-temperature synthesis-induced defect formation strategy presented here provides a new and facile way to synthesize stable MOFs with the combination of intrinsic micropore and additional mesopore as well as abundant Lewis acid sites.
A stable hierarchical porous metal-organic framework PCN-56 with abundant Lewis acid sites (denoted as Defective-PCN-56) was synthesized by the low-temperature synthesis-induced defect formation method. The existence of mesopore in structure was confirmed by N2 sorption isotherm and the successful encapsulation of large dye molecules. The Defective-PCN-56 has higher loading capacity toward anti-cancer drug Doxo compared with that of "nearly ideal-crystal" (denoted as Ideal-PCN-56) synthesized at high temperature, showing potential application as drug carrier. The low-temperature synthesis-induced defect formation strategy presented here provides a new and facile way to synthesize stable MOFs with the combination of intrinsic micropore and additional mesopore as well as abundant Lewis acid sites.
2019, 30(12): 2313-2317
doi: 10.1016/j.cclet.2019.05.047
Abstract:
In this study, impurity-free porous graphene (PG) with intrinsic pore structure was synthesized through a facile acid-alkali etching-assisted sonication approach. The pore structure appears on the surface of graphene sheets due to intrinsic defects of graphene. The PG possessed an extremely high specific surface area of 2184 m2/g, the size of~5 μm and layer numbers of 3-8. Additionally, PG contained micropores and mesopores simultaneously, with an average pore diameter of approximately 3 nm. The effects of acid, alkali, and ultrasound treatment on PG preparation were elucidated by transmission electron microscopy and fourier transform infrared spectroscopy. First, in an acidic solution, oxygen-containing functional groups (hydroxyls, carboxyl, and epoxides) were formed due to the hydrolysis of sulfate and continuous transformations of these functional groups on graphene oxide. Second, under the synergistic effects of alkali and ultrasound treatment, PG was obtained due to the loss of carboxyl and epoxide groups. A new route for preparing PG was provided by the proposed method.
In this study, impurity-free porous graphene (PG) with intrinsic pore structure was synthesized through a facile acid-alkali etching-assisted sonication approach. The pore structure appears on the surface of graphene sheets due to intrinsic defects of graphene. The PG possessed an extremely high specific surface area of 2184 m2/g, the size of~5 μm and layer numbers of 3-8. Additionally, PG contained micropores and mesopores simultaneously, with an average pore diameter of approximately 3 nm. The effects of acid, alkali, and ultrasound treatment on PG preparation were elucidated by transmission electron microscopy and fourier transform infrared spectroscopy. First, in an acidic solution, oxygen-containing functional groups (hydroxyls, carboxyl, and epoxides) were formed due to the hydrolysis of sulfate and continuous transformations of these functional groups on graphene oxide. Second, under the synergistic effects of alkali and ultrasound treatment, PG was obtained due to the loss of carboxyl and epoxide groups. A new route for preparing PG was provided by the proposed method.
2019, 30(12): 2318-2322
doi: 10.1016/j.cclet.2019.05.056
Abstract:
Sulfhydryl MCM-41 (SH-MCM-41) mesoporous materials were prepared via a hydrothermal method, and -SH was successfully imported by a post-grafting method. The structure and surface properties of the materials were characterized using Fourier Transform infrared spectroscopy, X-ray diffraction and Transmission Electron Microscopy analysis. The low concentrations of La3+, Gd3+ and Yb3+ adsorption on the material were investigated. This paper discusses the effects of system factors, such as pH and the solid-liquid ratio, on the performance of the adsorption process. The adsorption thermodynamics and kinetics were also explored. Experimental results indicated that the materials were in good order and had high specific surface area (956 m2/g) with an average pore diameter of 2.1 nm; the mercapto groups were successfully grafted onto a molecular sieve, and the best grafted amount was 1.46 ×10-3 mol/g. The materials showed preferable adsorption of La3+, Gd3+ and Yb3+ with maximum adsorption capacities of 560.56 mg/g, 467.60 mg/g and 540.68 mg/g, respectively. The adsorption process can be described by the Freundlich isotherm model, and the adsorption data fits pseudo-second-order kinetics. After repeating the elution-regeneration cycle four times, the adsorption capacity of rare earth ions was mostly maintained, indicating that the adsorbent can be regenerated well and recycled to save costs. It has potential in practical application.
Sulfhydryl MCM-41 (SH-MCM-41) mesoporous materials were prepared via a hydrothermal method, and -SH was successfully imported by a post-grafting method. The structure and surface properties of the materials were characterized using Fourier Transform infrared spectroscopy, X-ray diffraction and Transmission Electron Microscopy analysis. The low concentrations of La3+, Gd3+ and Yb3+ adsorption on the material were investigated. This paper discusses the effects of system factors, such as pH and the solid-liquid ratio, on the performance of the adsorption process. The adsorption thermodynamics and kinetics were also explored. Experimental results indicated that the materials were in good order and had high specific surface area (956 m2/g) with an average pore diameter of 2.1 nm; the mercapto groups were successfully grafted onto a molecular sieve, and the best grafted amount was 1.46 ×10-3 mol/g. The materials showed preferable adsorption of La3+, Gd3+ and Yb3+ with maximum adsorption capacities of 560.56 mg/g, 467.60 mg/g and 540.68 mg/g, respectively. The adsorption process can be described by the Freundlich isotherm model, and the adsorption data fits pseudo-second-order kinetics. After repeating the elution-regeneration cycle four times, the adsorption capacity of rare earth ions was mostly maintained, indicating that the adsorbent can be regenerated well and recycled to save costs. It has potential in practical application.
2019, 30(12): 2323-2327
doi: 10.1016/j.cclet.2019.06.040
Abstract:
The development of large-scale synthetic methods for high quality carbon quantum dots (CQDs) is fundamental to their applications. However, the macroscopic preparation and scale up synthetic of CQDs is still in its infancy. Here, we report a facile, green, kilogram-scale synthesis of high quality fluorescent CQDs derived from poplar leaves via a one-step hydrothermal method. Notably, the throughput of CQDs can reach a level up to as high as 1.4975 kg in one pot. The structure and properties of the as-prepared CQDs were assessed through TEM, XRD, XPS and various spectroscopic methods. The obtained high quality CQDs with a photoluminescent quantum yield of 10.64% showed remarkable stability in aqueous media, rich functional groups, high photostability, consistent photoluminescence within biological pH range and low cytotoxicity. On account of these good properties, we demonstrated the multifunctional application to electrocatalytic water splitting, Fe3+ sensing and bioimaging. It showed remarkable electrocatalytic activity, Fe3+ sensitivity and good biocompatibility. This study provides a green, facile, inexpensive and large-scale method for producing high quality CQDs, which provides application value for large-scale production of CQDs.
The development of large-scale synthetic methods for high quality carbon quantum dots (CQDs) is fundamental to their applications. However, the macroscopic preparation and scale up synthetic of CQDs is still in its infancy. Here, we report a facile, green, kilogram-scale synthesis of high quality fluorescent CQDs derived from poplar leaves via a one-step hydrothermal method. Notably, the throughput of CQDs can reach a level up to as high as 1.4975 kg in one pot. The structure and properties of the as-prepared CQDs were assessed through TEM, XRD, XPS and various spectroscopic methods. The obtained high quality CQDs with a photoluminescent quantum yield of 10.64% showed remarkable stability in aqueous media, rich functional groups, high photostability, consistent photoluminescence within biological pH range and low cytotoxicity. On account of these good properties, we demonstrated the multifunctional application to electrocatalytic water splitting, Fe3+ sensing and bioimaging. It showed remarkable electrocatalytic activity, Fe3+ sensitivity and good biocompatibility. This study provides a green, facile, inexpensive and large-scale method for producing high quality CQDs, which provides application value for large-scale production of CQDs.
2019, 30(12): 2328-2332
doi: 10.1016/j.cclet.2019.07.011
Abstract:
In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithium-oxygen batteries (Li-O2 batteries), most efforts currently focus on the design of rational porous architectures. Only few works study the surface chemistry effect that might be a critical factor influencing the capacities of carbonaceous electrodes. In addition, the surface chemistry effect is very difficult to be studied in composite electrodes due to the influences of binders and additives. Herein, we propose chemically activated carbon cloth (CACC) as an ideal model to investigate the effect of surface functional groups on the discharge capacities of carbonaceous oxygen electrodes for Li-O2 batteries. The intrinsic surface chemistry effect on the performance of carbonaceous cathode is directly observed for the first time without the influences of binders and additives. Results indicate that the surface carboxyl groups introduced by the chemical treatment not only function as the appropriate nucleation sites for Li2O2 but also induce the formation of toroid-like Li2O2. Thus, the surface carboxyl modification enhances the discharge capacities from 0.48 mAh/cm2 of pristine carbon cloth to 1.23 mAh/cm2 of CACC. This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering.
In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithium-oxygen batteries (Li-O2 batteries), most efforts currently focus on the design of rational porous architectures. Only few works study the surface chemistry effect that might be a critical factor influencing the capacities of carbonaceous electrodes. In addition, the surface chemistry effect is very difficult to be studied in composite electrodes due to the influences of binders and additives. Herein, we propose chemically activated carbon cloth (CACC) as an ideal model to investigate the effect of surface functional groups on the discharge capacities of carbonaceous oxygen electrodes for Li-O2 batteries. The intrinsic surface chemistry effect on the performance of carbonaceous cathode is directly observed for the first time without the influences of binders and additives. Results indicate that the surface carboxyl groups introduced by the chemical treatment not only function as the appropriate nucleation sites for Li2O2 but also induce the formation of toroid-like Li2O2. Thus, the surface carboxyl modification enhances the discharge capacities from 0.48 mAh/cm2 of pristine carbon cloth to 1.23 mAh/cm2 of CACC. This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering.
2019, 30(12): 2333-2337
doi: 10.1016/j.cclet.2019.07.007
Abstract:
Self-cleaning surfaces are desirable in many engineering applications where low energy consumption, reusability and sustainability are of the biggest concerns. Inspired by the gecko's unique 'dry selfcleaning' hierarchical structures. Here we fabricated artificial Fe3O4/PDMS composites that show robust self-cleaning capabilities. The enhanced adhesion performance is attributable to the decrease of PDMS polymerization degree and the load transfer between PDMS matrix and Fe3O4 magnetic particles. The self-cleaning surfaces showed up to 24.3% self-cleaning rate with as few as 4 steps. Simulation result indicated that the changing of cross linking between Fe3O4 and PDMS is the main reason for the enhanced self-cleaning surfaces. This work reveals an alternative route of making high-performance self-cleaning smart surfaces that are applicable in the textile industry, robotic locomotion/gripping technology, outerspace explorations and tissue engineering.
Self-cleaning surfaces are desirable in many engineering applications where low energy consumption, reusability and sustainability are of the biggest concerns. Inspired by the gecko's unique 'dry selfcleaning' hierarchical structures. Here we fabricated artificial Fe3O4/PDMS composites that show robust self-cleaning capabilities. The enhanced adhesion performance is attributable to the decrease of PDMS polymerization degree and the load transfer between PDMS matrix and Fe3O4 magnetic particles. The self-cleaning surfaces showed up to 24.3% self-cleaning rate with as few as 4 steps. Simulation result indicated that the changing of cross linking between Fe3O4 and PDMS is the main reason for the enhanced self-cleaning surfaces. This work reveals an alternative route of making high-performance self-cleaning smart surfaces that are applicable in the textile industry, robotic locomotion/gripping technology, outerspace explorations and tissue engineering.
2019, 30(12): 2338-2342
doi: 10.1016/j.cclet.2019.07.021
Abstract:
In this paper, a new two-dimensional (2D)/2D composite of Bi2WO6/MoS2 was facile synthesized, and then was used as supporting material for depositing Pt nanoparticles. The as-synthesized Pt-Bi2WO6/MoS2 was extended into photo-assisted electrocatalytic oxidation of methanol, which is a model anode reaction for direct methanol fuel cell. Compare with traditional electrocatalytic process, Pt-Bi2WO6/MoS2 displays 1.5 times enhanced electrocatalytic performance on methanol oxidation with assistance of visible light irradiation and 2.2 times for commercial Pt/C. Besides, from the results of chronoamperometric and chronopotentiometry experiments, the stability of Pt-Bi2WO6/MoS2 electrode is clearly improved under visible light irradiation. The synergistic effects of photo-and electro-catalytic in the heterojunction of Pt-Bi2WO6/MoS2 in favor of the above enhancement. This research gives more insights in the fields of photo-assisted traditional electrocatalytic application by constructing of semiconductor heterojunction carrier.
In this paper, a new two-dimensional (2D)/2D composite of Bi2WO6/MoS2 was facile synthesized, and then was used as supporting material for depositing Pt nanoparticles. The as-synthesized Pt-Bi2WO6/MoS2 was extended into photo-assisted electrocatalytic oxidation of methanol, which is a model anode reaction for direct methanol fuel cell. Compare with traditional electrocatalytic process, Pt-Bi2WO6/MoS2 displays 1.5 times enhanced electrocatalytic performance on methanol oxidation with assistance of visible light irradiation and 2.2 times for commercial Pt/C. Besides, from the results of chronoamperometric and chronopotentiometry experiments, the stability of Pt-Bi2WO6/MoS2 electrode is clearly improved under visible light irradiation. The synergistic effects of photo-and electro-catalytic in the heterojunction of Pt-Bi2WO6/MoS2 in favor of the above enhancement. This research gives more insights in the fields of photo-assisted traditional electrocatalytic application by constructing of semiconductor heterojunction carrier.
2019, 30(12): 2343-2346
doi: 10.1016/j.cclet.2019.07.023
Abstract:
Improving the performance and reducing the manufacturing costs are the main directions for the development of organic solar cells in the future. Here, the strategy that uses chemical structure modification to optimize the photoelectric properties is reported. A new narrow bandgap (1.30 eV) chlorinated non-fullerene electron acceptor (Y15), based on benzo[d] [1 , 2 , 3 ] triazole triazole with two 3-undecylthieno[2', 3':4, 5] thieno[3, 2-b] pyrrole fused -7-heterocyclic ring, with absorption edge extending to the near-infrared (NIR) region, namely A-DA'D-A type structure, is designed and synthesized. Its electrochemical and optoelectronic properties are systematically investigated. Benefitting from its NIR light harvesting, the fabricated photovoltaic devices based on Y15 deliver a high power conversion efficiency (PCE) of 14.13%, when blending with a wide bandgap polymer donor PM6. Our results show that the A-DA'D-A type molecular design and application of near-infrared electron acceptors have the potential to further improve the PCE of polymer solar cells (PSCs).
Improving the performance and reducing the manufacturing costs are the main directions for the development of organic solar cells in the future. Here, the strategy that uses chemical structure modification to optimize the photoelectric properties is reported. A new narrow bandgap (1.30 eV) chlorinated non-fullerene electron acceptor (Y15), based on benzo[d] [
2019, 30(12): 2347-2350
doi: 10.1016/j.cclet.2019.07.024
Abstract:
In the work, we propose an efficient one-pot approach for synthesis of a new type of mesoporous silica nanoparticles (MSNs). That can be successfully realized by using tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD) as the silica precursors and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent through a facile assembly process. The as-synthesized MSNs possess a spherical morphology with about 230 nm, a relatively high surface area of 133 m2/g, and a hierarchical pore size distribution. When applied as the sorbents, the amine-functioned MSNs demonstrate the enhanced adsorption capacity for CO2 capture (at 1 bar, 15 vol% CO2, up to 80.5 mg/g at 75℃), high selectivity, and good cycling durability, benefiting from the suitable modification of polyethyleneimine.
In the work, we propose an efficient one-pot approach for synthesis of a new type of mesoporous silica nanoparticles (MSNs). That can be successfully realized by using tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD) as the silica precursors and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent through a facile assembly process. The as-synthesized MSNs possess a spherical morphology with about 230 nm, a relatively high surface area of 133 m2/g, and a hierarchical pore size distribution. When applied as the sorbents, the amine-functioned MSNs demonstrate the enhanced adsorption capacity for CO2 capture (at 1 bar, 15 vol% CO2, up to 80.5 mg/g at 75℃), high selectivity, and good cycling durability, benefiting from the suitable modification of polyethyleneimine.
2019, 30(12): 2351-2354
doi: 10.1016/j.cclet.2019.08.007
Abstract:
Encapsulation of bioactive substances for extended shelf life and controlled, targeted release is critical for their applications in food and drug delivery. Here, a new method has been developed to encapsulate bioactive molecules in the crystal composites, showing greatly enhanced stability and unique pH-triggered response. Chlorophyll, a model bioactive, is first loaded in shellac nanoparticles via coprecipitation with a high encapsulation efficiency, and then the chlorophyll-loaded nanoparticles are incorporated into calcite crystals grown from a gel media containing the nanoparticles. Under the protection of shellac nanoparticles and calcite crystals, chlorophyll shows excellent stability even under light. Encapsulated chlorophyll could only be released by first dissolving the calcite crystals under acidic condition and then dissolving the shellac nanoparticles under alkaline condition. The unique pH-triggered release mimics the pH change from acidic in the stomach to alkaline in the intestine and is thus well suited for controlled, targeted intestinal release. This work suggests that the crystal composites are an ideal delivery vehicle for the functional design of bioactive molecules.
Encapsulation of bioactive substances for extended shelf life and controlled, targeted release is critical for their applications in food and drug delivery. Here, a new method has been developed to encapsulate bioactive molecules in the crystal composites, showing greatly enhanced stability and unique pH-triggered response. Chlorophyll, a model bioactive, is first loaded in shellac nanoparticles via coprecipitation with a high encapsulation efficiency, and then the chlorophyll-loaded nanoparticles are incorporated into calcite crystals grown from a gel media containing the nanoparticles. Under the protection of shellac nanoparticles and calcite crystals, chlorophyll shows excellent stability even under light. Encapsulated chlorophyll could only be released by first dissolving the calcite crystals under acidic condition and then dissolving the shellac nanoparticles under alkaline condition. The unique pH-triggered release mimics the pH change from acidic in the stomach to alkaline in the intestine and is thus well suited for controlled, targeted intestinal release. This work suggests that the crystal composites are an ideal delivery vehicle for the functional design of bioactive molecules.
2019, 30(12): 2355-2358
doi: 10.1016/j.cclet.2019.09.027
Abstract:
The self-assembly of L-tryptophan on Cu(111) is investigated by an ultrahigh vacuum scanning tunneling microscope (STM) at 4.4 K. When deposited onto the substrate at around 120 K with a coverage of 0.1 monolayer, molecular trimers, tetramers, hexamers, and chains coexist on Cu(111). Then almost all molecules self-assemble into chiral hexamers after being annealed at room temperature. When increasing molecular coverage to the full layer, a new type of chain is observed on the surface. Based on the high-resolution STM images at sub-molecular level, we suggest that the L-tryptophan molecules are present in neutral, zwitterionic or anionic states in these structures.
The self-assembly of L-tryptophan on Cu(111) is investigated by an ultrahigh vacuum scanning tunneling microscope (STM) at 4.4 K. When deposited onto the substrate at around 120 K with a coverage of 0.1 monolayer, molecular trimers, tetramers, hexamers, and chains coexist on Cu(111). Then almost all molecules self-assemble into chiral hexamers after being annealed at room temperature. When increasing molecular coverage to the full layer, a new type of chain is observed on the surface. Based on the high-resolution STM images at sub-molecular level, we suggest that the L-tryptophan molecules are present in neutral, zwitterionic or anionic states in these structures.
2019, 30(12): 2359-2362
doi: 10.1016/j.cclet.2019.10.033
Abstract:
A simple visual method for DNA detection during the formation of gold nanoparticles (AuNPs) was developed based on different electrostatic properties of single strand DNA (ssDNA) and double strand DNA (dsDNA). Since the ssDNA is easy to bind to AuNPs due to its exposed bases which could prevent saltinduced aggregation of AuNPs. The dsDNA always present negative charge because its negatively charged phosphate backbone is exposed. In this case, the dsDNA could disturb the adsorption between dsDNA and AuNPs and result in non-aggregation of AuNPs. After hybridization, chloroauric acid and ascorbic acid were added to the mixture solution, and the solution changed to red immediately and turned to purple in 10 min in the present of target DNA. TEM results confirmed that the change of color stemed from aggregation of AuNPs. In order to obtain accurate results by naked eye, the DNA detection assay should be conducted under pH 7.0.
A simple visual method for DNA detection during the formation of gold nanoparticles (AuNPs) was developed based on different electrostatic properties of single strand DNA (ssDNA) and double strand DNA (dsDNA). Since the ssDNA is easy to bind to AuNPs due to its exposed bases which could prevent saltinduced aggregation of AuNPs. The dsDNA always present negative charge because its negatively charged phosphate backbone is exposed. In this case, the dsDNA could disturb the adsorption between dsDNA and AuNPs and result in non-aggregation of AuNPs. After hybridization, chloroauric acid and ascorbic acid were added to the mixture solution, and the solution changed to red immediately and turned to purple in 10 min in the present of target DNA. TEM results confirmed that the change of color stemed from aggregation of AuNPs. In order to obtain accurate results by naked eye, the DNA detection assay should be conducted under pH 7.0.
2019, 30(12): 2363-2367
doi: 10.1016/j.cclet.2019.07.020
Abstract:
A novel architecture of CdS/ZnO nanorods with plasmonic silver (Ag) nanoparticles deposited at the interface of ZnO nanorods and CdS nanocrystallites, was designed as a photoanode for solar hydrogen generation, with photocurrent density achieving 4.7 mA/cm2 at 1.6 V (vs. RHE), which is 8 and 1.7 times as high as those of pure ZnO and CdS/ZnO nanorod films, respectively. Additionally, with optical absorption onset extended to~660 nm, CdS/Ag/ZnO nanorod film exhibits significantly increased incident photo-to-current efficiency (IPCE) in the whole optical absorption region, reaching 23.1% and 9.8% at 400 nm and 500 nm, respectively. The PEC enhancement can be attributed to the one-dimensional ZnO nanorod structure maintained for superior charge transfer, and the extended visible-light absorption of CdS nanocrystallites. Moreover, the incorporated plasmonic Ag nanoparticles could further promote the interfacial charge carrier transfer process and enhance the optical absorption ability, due to its excellent plasmon resonance effect.
A novel architecture of CdS/ZnO nanorods with plasmonic silver (Ag) nanoparticles deposited at the interface of ZnO nanorods and CdS nanocrystallites, was designed as a photoanode for solar hydrogen generation, with photocurrent density achieving 4.7 mA/cm2 at 1.6 V (vs. RHE), which is 8 and 1.7 times as high as those of pure ZnO and CdS/ZnO nanorod films, respectively. Additionally, with optical absorption onset extended to~660 nm, CdS/Ag/ZnO nanorod film exhibits significantly increased incident photo-to-current efficiency (IPCE) in the whole optical absorption region, reaching 23.1% and 9.8% at 400 nm and 500 nm, respectively. The PEC enhancement can be attributed to the one-dimensional ZnO nanorod structure maintained for superior charge transfer, and the extended visible-light absorption of CdS nanocrystallites. Moreover, the incorporated plasmonic Ag nanoparticles could further promote the interfacial charge carrier transfer process and enhance the optical absorption ability, due to its excellent plasmon resonance effect.
2019, 30(12): 2368-2374
doi: 10.1016/j.cclet.2019.11.021
Abstract:
The prevalence of functionalized nanoparticles in biological and clinical fields attracts intensive toxicology investigations. Minimizing the nanoparticles' biohazard remains a challenge due to the insufficient understanding on the nanoparticle-induced cell death mechanism. In the presented study, we observed the lysosome and genome injuries and so caused cell cycle changes and regulations of retinal ganglion neuron cell 5 (RGC-5) induced by aminated and alkylated nanoparticles. Alkylated nanoparticles induced malignant lysosome and genome damages followed by severe post-self-repair responses. RGC-5 treated with alkylated nanoparticles presented dramatic S phase prolongation resulted from cyclin E accumulation mediated by Fbw7 downregulation, which assisted DNA replication after failed self-repair of the malignantly damaged DNA caused by alkylated nanoparticles. Differently, aminated nanoparticles in RGC-5 induced moderate lysosome and genome injuries and these damages could be repaired in the p21-involved pathway, so that cells did not induce apparent cyclin E accumulation nor Fbw7 downregulation as post-self-repair response. These results helped us to understand the toxicity of analogous nanoparticles on retinal ganglions such as glaucoma treatment. This work provides new insights into nanoparticle functionalization and toxicity in relation to the research on the toxicology and pathology of nerve cells.
The prevalence of functionalized nanoparticles in biological and clinical fields attracts intensive toxicology investigations. Minimizing the nanoparticles' biohazard remains a challenge due to the insufficient understanding on the nanoparticle-induced cell death mechanism. In the presented study, we observed the lysosome and genome injuries and so caused cell cycle changes and regulations of retinal ganglion neuron cell 5 (RGC-5) induced by aminated and alkylated nanoparticles. Alkylated nanoparticles induced malignant lysosome and genome damages followed by severe post-self-repair responses. RGC-5 treated with alkylated nanoparticles presented dramatic S phase prolongation resulted from cyclin E accumulation mediated by Fbw7 downregulation, which assisted DNA replication after failed self-repair of the malignantly damaged DNA caused by alkylated nanoparticles. Differently, aminated nanoparticles in RGC-5 induced moderate lysosome and genome injuries and these damages could be repaired in the p21-involved pathway, so that cells did not induce apparent cyclin E accumulation nor Fbw7 downregulation as post-self-repair response. These results helped us to understand the toxicity of analogous nanoparticles on retinal ganglions such as glaucoma treatment. This work provides new insights into nanoparticle functionalization and toxicity in relation to the research on the toxicology and pathology of nerve cells.
2019, 30(12): 2051-2052
doi: 10.1016/j.cclet.2019.10.038
Abstract:
It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells. These functions were widely achieved by attaching functional peptides to the surface of biomaterials. It is well known that an antifouling layer can help reducing the nonspecific cell attachment. However, it is unclear how an antifouling PEG layer affects the function of peptides attached on material surface in controlling cell behavior. This highlight introduced the recent JACS paper from Prof. Liu and coworkers in addressing this question thoroughly.
It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells. These functions were widely achieved by attaching functional peptides to the surface of biomaterials. It is well known that an antifouling layer can help reducing the nonspecific cell attachment. However, it is unclear how an antifouling PEG layer affects the function of peptides attached on material surface in controlling cell behavior. This highlight introduced the recent JACS paper from Prof. Liu and coworkers in addressing this question thoroughly.
2019, 30(12): 2053-2064
doi: 10.1016/j.cclet.2019.10.028
Abstract:
Energy storage and conversion have attained significant interest owing to its important applications that reduce CO2 emission through employing green energy. Some promising technologies are included metalair batteries, metal-sulfur batteries, metal-ion batteries, electrochemical capacitors, etc. Here, metal elements are involved with lithium, sodium, and magnesium. For these devices, electrode materials are of importance to obtain high performance. Two-dimensional (2D) materials are a large kind of layered structured materials with promising future as energy storage materials, which include graphene, black phosporus, MXenes, covalent organic frameworks (COFs), 2D oxides, 2D chalcogenides, and others. Great progress has been achieved to go ahead for 2D materials in energy storage and conversion. More researchers will join in this research field. Under the background, it has motivated us to contribute with a roadmap on two-dimensional materials for energy storage and conversion.
Energy storage and conversion have attained significant interest owing to its important applications that reduce CO2 emission through employing green energy. Some promising technologies are included metalair batteries, metal-sulfur batteries, metal-ion batteries, electrochemical capacitors, etc. Here, metal elements are involved with lithium, sodium, and magnesium. For these devices, electrode materials are of importance to obtain high performance. Two-dimensional (2D) materials are a large kind of layered structured materials with promising future as energy storage materials, which include graphene, black phosporus, MXenes, covalent organic frameworks (COFs), 2D oxides, 2D chalcogenides, and others. Great progress has been achieved to go ahead for 2D materials in energy storage and conversion. More researchers will join in this research field. Under the background, it has motivated us to contribute with a roadmap on two-dimensional materials for energy storage and conversion.
2019, 30(12): 2065-2088
doi: 10.1016/j.cclet.2019.11.001
Abstract:
Environmental catalysis hasdrawna great deal ofattention due to its cleanwaysto produce usefulchemicals or carry out some chemical processes. Photocatalysis and electrocatalysis play important roles in these fields. They can decompose and remove organic pollutants from the aqueous environment, and prepare some fine chemicals. Moreover, they also can carry out some important reactions, such as O2 reduction reaction (ORR), O2 evolution reaction (OER), H2 evolution reaction (HER), CO2 reduction reaction (CO2RR), and N2 fixation (NRR). For catalytic reactions, it is the key to develop high-performance catalysts to meet the demand for targeted reactions. In recentyears, two-dimensional(2D) materials have attracted great interest in environmental catalysis due to their unique layered structures, which offer us to make use of their electronic and structural characteristics. Great progress has been made so far, including graphene, black phosphorus, oxides, layered double hydroxides (LDHs), chalcogenides, bismuth-based layered compounds, MXenes, metal organic frameworks (MOFs), covalent organic frameworks (COFs), and others. This content drives us to invite many famous groups in these fields to write the roadmap on two-dimensional nanomaterials for environmental catalysis. We hope that this roadmap can give the useful guidance to researchers in future researches, and provide the research directions.
Environmental catalysis hasdrawna great deal ofattention due to its cleanwaysto produce usefulchemicals or carry out some chemical processes. Photocatalysis and electrocatalysis play important roles in these fields. They can decompose and remove organic pollutants from the aqueous environment, and prepare some fine chemicals. Moreover, they also can carry out some important reactions, such as O2 reduction reaction (ORR), O2 evolution reaction (OER), H2 evolution reaction (HER), CO2 reduction reaction (CO2RR), and N2 fixation (NRR). For catalytic reactions, it is the key to develop high-performance catalysts to meet the demand for targeted reactions. In recentyears, two-dimensional(2D) materials have attracted great interest in environmental catalysis due to their unique layered structures, which offer us to make use of their electronic and structural characteristics. Great progress has been made so far, including graphene, black phosphorus, oxides, layered double hydroxides (LDHs), chalcogenides, bismuth-based layered compounds, MXenes, metal organic frameworks (MOFs), covalent organic frameworks (COFs), and others. This content drives us to invite many famous groups in these fields to write the roadmap on two-dimensional nanomaterials for environmental catalysis. We hope that this roadmap can give the useful guidance to researchers in future researches, and provide the research directions.
2019, 30(12): 2089-2109
doi: 10.1016/j.cclet.2019.10.041
Abstract:
Green reactions not only provide us chemical products without any pollution, but also offer us the viable technology to realize difficult tasks in normal conditions. Photo-, photoelectro-, and electrocatalytic reactions are indeed powerful tools to help us to embrace bright future. Especially, some gas-involved reactions are extremely useful to change our life environments from energy systems to liquid fuels and cost-effective products, such as H2 evolution (H2 production), O2 evolution/reduction, CO2 reduction, N2 reduction (or N2 fixation) reactions. We can provide fuel cells clean H2 for electric vehicles from H2 evolution reaction (HER), at the same time, we also need highly efficient O2 reduction reaction (ORR) in fuel cells for improving the reaction kinetics. Moreover, we can get the clean oxidant O2 from water through O2 evolution reaction (OER), and carry out some reactions without posing any pollution to reaction systems. Furthermore, we can translate the greenhouse gas CO2 into useful liquid fuels through CO2 reduction reaction (CRR). Last but not the least, we can get ammonia from N2 reduction reaction (NRR), which can decrease energy input compared to the traditional Hubble process. These reactions, such as HER, ORR, OER, CRR and NRR could be realized through solar-, photoelectro-and electro-assisted ways. For them, the catalysts used play crucial roles in determining the efficiency and kinds of products, so we should consider the efficiency of catalysts. However, the cost, synthetic methods of catalysts should also be considered. Nowadays, significant progress has been achieved, however, many challenges still exist, reaction systems, catalysts underlying mechanisms, and so on. As extremely active fields, we should pay attention to them. Under the background, it has motivated us to contribute with a roadmap on 'GasInvolved Photo-and Electro-Catalysis'.
Green reactions not only provide us chemical products without any pollution, but also offer us the viable technology to realize difficult tasks in normal conditions. Photo-, photoelectro-, and electrocatalytic reactions are indeed powerful tools to help us to embrace bright future. Especially, some gas-involved reactions are extremely useful to change our life environments from energy systems to liquid fuels and cost-effective products, such as H2 evolution (H2 production), O2 evolution/reduction, CO2 reduction, N2 reduction (or N2 fixation) reactions. We can provide fuel cells clean H2 for electric vehicles from H2 evolution reaction (HER), at the same time, we also need highly efficient O2 reduction reaction (ORR) in fuel cells for improving the reaction kinetics. Moreover, we can get the clean oxidant O2 from water through O2 evolution reaction (OER), and carry out some reactions without posing any pollution to reaction systems. Furthermore, we can translate the greenhouse gas CO2 into useful liquid fuels through CO2 reduction reaction (CRR). Last but not the least, we can get ammonia from N2 reduction reaction (NRR), which can decrease energy input compared to the traditional Hubble process. These reactions, such as HER, ORR, OER, CRR and NRR could be realized through solar-, photoelectro-and electro-assisted ways. For them, the catalysts used play crucial roles in determining the efficiency and kinds of products, so we should consider the efficiency of catalysts. However, the cost, synthetic methods of catalysts should also be considered. Nowadays, significant progress has been achieved, however, many challenges still exist, reaction systems, catalysts underlying mechanisms, and so on. As extremely active fields, we should pay attention to them. Under the background, it has motivated us to contribute with a roadmap on 'GasInvolved Photo-and Electro-Catalysis'.
2019, 30(12): 2110-2122
doi: 10.1016/j.cclet.2019.11.022
Abstract:
Porous materials have attracted great attention in energy and environment applications, such as metal organic frameworks (MOFs), metal aerogels, carbon aerogels, porous metal oxides. These materials could be also hybridized with other materials into functional composites with superior properties. The high specific area of porous materials offer them the advantage as hosts to conduct catalytic and electrochemical reactions. On one hand, catalytic reactions include photocatalytic, photoelectrocatalytic and electrocatalytic reactions over some gases. On the other hand, they can be used as electrodes in various batteries, such as alkaline metal ion batteries and electrochemical capacitors. So far, both catalysis and batteries are extremely attractive topics. There are also many obstacles to overcome in the exploration of these porous materials. The research related to porous materials for energy and environment applications is at extremely active stage, and this has motivated us to contribute with a roadmap on nporous materials for energy and environment applications'.
Porous materials have attracted great attention in energy and environment applications, such as metal organic frameworks (MOFs), metal aerogels, carbon aerogels, porous metal oxides. These materials could be also hybridized with other materials into functional composites with superior properties. The high specific area of porous materials offer them the advantage as hosts to conduct catalytic and electrochemical reactions. On one hand, catalytic reactions include photocatalytic, photoelectrocatalytic and electrocatalytic reactions over some gases. On the other hand, they can be used as electrodes in various batteries, such as alkaline metal ion batteries and electrochemical capacitors. So far, both catalysis and batteries are extremely attractive topics. There are also many obstacles to overcome in the exploration of these porous materials. The research related to porous materials for energy and environment applications is at extremely active stage, and this has motivated us to contribute with a roadmap on nporous materials for energy and environment applications'.
