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2021 Volume 32 Issue 8
2021, 32(8): 2347-2358
doi: 10.1016/j.cclet.2021.03.015
Abstract:
Extensive research has been performed on cell membrane camouflaged-based drug delivery systems in recent years. Herein, we provide an overview of the challenges in system preparation, functional design, continuous industrial production of these systems, and solution strategies for these challenges. Further, we analyze and discuss the frontier medical applications of cell membrane-camouflaged drug delivery systems in anti-inflammatory, anti-pathogenic microorganisms, and biological detoxification. This review takes a challenge-oriented perspective and seeks innovative strategies, provides a literature review of research into cell membrane-camouflaged drug delivery systems, and promotes the development of personalized clinical treatments.
Extensive research has been performed on cell membrane camouflaged-based drug delivery systems in recent years. Herein, we provide an overview of the challenges in system preparation, functional design, continuous industrial production of these systems, and solution strategies for these challenges. Further, we analyze and discuss the frontier medical applications of cell membrane-camouflaged drug delivery systems in anti-inflammatory, anti-pathogenic microorganisms, and biological detoxification. This review takes a challenge-oriented perspective and seeks innovative strategies, provides a literature review of research into cell membrane-camouflaged drug delivery systems, and promotes the development of personalized clinical treatments.
2021, 32(8): 2359-2368
doi: 10.1016/j.cclet.2021.03.020
Abstract:
The photoisomerization properties of azo derivatives have been widely used in the fields of materials and biology. One serious restriction to the development of functional azo-based materials is the necessity to trigger switching by UV light, which damage the corresponding surfaces and penetrate only partially through the matter. Therefore, developing the visible and near-infrared light activated azo switches can solve this problem. This review provides a summary of molecular design strategies for driving the isomerization of azo derivatives with visible light and near-infrared light: (1) smart design directly excited by visible light, (2) the addition of upconversion nanoparticles, (3) the employment of two-photon absorption, (4) indirect excitation in combination with metal sensitizer.
The photoisomerization properties of azo derivatives have been widely used in the fields of materials and biology. One serious restriction to the development of functional azo-based materials is the necessity to trigger switching by UV light, which damage the corresponding surfaces and penetrate only partially through the matter. Therefore, developing the visible and near-infrared light activated azo switches can solve this problem. This review provides a summary of molecular design strategies for driving the isomerization of azo derivatives with visible light and near-infrared light: (1) smart design directly excited by visible light, (2) the addition of upconversion nanoparticles, (3) the employment of two-photon absorption, (4) indirect excitation in combination with metal sensitizer.
2021, 32(8): 2369-2379
doi: 10.1016/j.cclet.2021.03.016
Abstract:
Living-cell imaging demands high specificity, sensitivity, and minimal background interference to the targets of interest. However, developing a desirable imaging probe that can possess all the above features is still challenging. The bioorthogonal surface-enhanced Raman scattering (SERS) imaging has been recently emerged through utilizing Raman reporters with characteristic peaks in Raman-silent region of cells (1800-2800 cm-1), which opens a revolutionary avenue for living-cell imaging with multiplexing capability. In this review, we focus on the recent advances in the technology development and the biological and biomedical applications of the living-cell bioorthogonal SERS imaging technique. After introduction of fundamental principles for bioorthogonal tag or label, we present applications for visualization of various intracellular components and environment including proteins, nucleic acids, lipids, pH and hypoxia, even for cancer diagnosis in tissue samples. Then, various bioorthogonal SERS imaging-guided therapy strategies have been discussed such as phototherapy and surgery. In conclusion, this strategy has great potential to be a flexible and robust tool for visualization detection and diseases diagnosis.
Living-cell imaging demands high specificity, sensitivity, and minimal background interference to the targets of interest. However, developing a desirable imaging probe that can possess all the above features is still challenging. The bioorthogonal surface-enhanced Raman scattering (SERS) imaging has been recently emerged through utilizing Raman reporters with characteristic peaks in Raman-silent region of cells (1800-2800 cm-1), which opens a revolutionary avenue for living-cell imaging with multiplexing capability. In this review, we focus on the recent advances in the technology development and the biological and biomedical applications of the living-cell bioorthogonal SERS imaging technique. After introduction of fundamental principles for bioorthogonal tag or label, we present applications for visualization of various intracellular components and environment including proteins, nucleic acids, lipids, pH and hypoxia, even for cancer diagnosis in tissue samples. Then, various bioorthogonal SERS imaging-guided therapy strategies have been discussed such as phototherapy and surgery. In conclusion, this strategy has great potential to be a flexible and robust tool for visualization detection and diseases diagnosis.
2021, 32(8): 2544-2550
doi: 10.1016/j.cclet.2021.01.028
Abstract:
Recently, the degradation of organic compounds in saline dye wastewater by sulfate radicals (SO4·-)-based advanced oxidation processes (AOPs) have attracted much attention. However, previous studies on these systems have selected non-chlorinated dyes as model compounds, and little is known about the transformation of chlorinated dyes in such systems. In this study, acid yellow 17 (AY-17) was selected as a model of chlorinated contaminants, and the degradation kinetics and evolution of oxidation byproducts were investigated in the UV/PDS system. AY-17 can be efficiently degraded (over 98% decolorization) under 90 min irradiation at pH 2.0–3.0, and the reaction follows pseudo-first order kinetics. Cl- accelerated the degradation of AY-17, but simultaneously led to an undesirable increase of absorbable organic halogen (AOX). Several chlorinated byproducts were identified by liquid chromatography-mass spectrometry (LC–MS/MS) in the UV/PDS system. It indicates that endogenic chlorine and exogenic Cl– reacted with SO4·- to form chloride radicals, which are involved in the dechlorination and rechlorination of AY-17 and intermediates. The possible degradation mechanisms of AY-17 photooxidative degradation are proposed. This work provides valuable information for further studies on the role of exogenic chloride in the degradation of chlorinated azo dyes and the kinetic parameters in the PDS-based oxidation process.
Recently, the degradation of organic compounds in saline dye wastewater by sulfate radicals (SO4·-)-based advanced oxidation processes (AOPs) have attracted much attention. However, previous studies on these systems have selected non-chlorinated dyes as model compounds, and little is known about the transformation of chlorinated dyes in such systems. In this study, acid yellow 17 (AY-17) was selected as a model of chlorinated contaminants, and the degradation kinetics and evolution of oxidation byproducts were investigated in the UV/PDS system. AY-17 can be efficiently degraded (over 98% decolorization) under 90 min irradiation at pH 2.0–3.0, and the reaction follows pseudo-first order kinetics. Cl- accelerated the degradation of AY-17, but simultaneously led to an undesirable increase of absorbable organic halogen (AOX). Several chlorinated byproducts were identified by liquid chromatography-mass spectrometry (LC–MS/MS) in the UV/PDS system. It indicates that endogenic chlorine and exogenic Cl– reacted with SO4·- to form chloride radicals, which are involved in the dechlorination and rechlorination of AY-17 and intermediates. The possible degradation mechanisms of AY-17 photooxidative degradation are proposed. This work provides valuable information for further studies on the role of exogenic chloride in the degradation of chlorinated azo dyes and the kinetic parameters in the PDS-based oxidation process.
2021, 32(8): 2551-2554
doi: 10.1016/j.cclet.2021.02.054
Abstract:
Ynamides are electron-rich alkynes with unique reactivities and act as flexible building blocks in organic synthesis. Therefore, the investigation for transformation of ynamides with exceptional selectivity and efficiency is attractive and interesting. Herein, we report an oxoarylation of ynamides with N-aryl hydroxamic acids. In the presence of catalytic Cu(OTf)2, both the terminal and internal ynamides could undergo an addition/[3,3] sigmatropic rearrangement cascade with N-aryl hydroxamic acids to achieve oxoarylation, along with providing selective entry to (ortho-amino)arylacetamides and oxindoles. Moreover, deuterium-labelling reaction and gram-scale reaction were conducted to probe the mechanism and showcase the scalability.
Ynamides are electron-rich alkynes with unique reactivities and act as flexible building blocks in organic synthesis. Therefore, the investigation for transformation of ynamides with exceptional selectivity and efficiency is attractive and interesting. Herein, we report an oxoarylation of ynamides with N-aryl hydroxamic acids. In the presence of catalytic Cu(OTf)2, both the terminal and internal ynamides could undergo an addition/[3,3] sigmatropic rearrangement cascade with N-aryl hydroxamic acids to achieve oxoarylation, along with providing selective entry to (ortho-amino)arylacetamides and oxindoles. Moreover, deuterium-labelling reaction and gram-scale reaction were conducted to probe the mechanism and showcase the scalability.
2021, 32(8): 2555-2558
doi: 10.1016/j.cclet.2021.02.052
Abstract:
Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity, providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.
Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity, providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.
2021, 32(8): 2559-2561
doi: 10.1016/j.cclet.2021.02.018
Abstract:
An efficient and facile method for C–H amination of quinoxalinones with heteroaromatic amines under metal-free conditions has been described. In the presence of hypervalent PIDA reagent, the desired products with various groups were obtained with moderate to high yields.
An efficient and facile method for C–H amination of quinoxalinones with heteroaromatic amines under metal-free conditions has been described. In the presence of hypervalent PIDA reagent, the desired products with various groups were obtained with moderate to high yields.
2021, 32(8): 2562-2566
doi: 10.1016/j.cclet.2021.02.022
Abstract:
A series of multi-(phenylthio)porphyrinato Ni(ò) compounds were synthesized without the participation of transition metal catalysts. All of these products were well characterized by 1H NMR, 13C NMR and HRMS. Structures of three typical compounds were further confirmed by X-ray single crystal diffraction. Remarkable red shifts were observed in UVɃvis absorption spectra of multi-(phenylthio)porphyrinato Ni(ò) compounds which meet well with the electrochemical data. DFT calculation indicates that the phenylthio groups have strong effects on the frontier orbitals of these molecules. The order of a1u-like and a2u-like orbitals mainly distributed in porphyrin moiety is often inversed in energy when multi-phenylthio groups are attached.
A series of multi-(phenylthio)porphyrinato Ni(ò) compounds were synthesized without the participation of transition metal catalysts. All of these products were well characterized by 1H NMR, 13C NMR and HRMS. Structures of three typical compounds were further confirmed by X-ray single crystal diffraction. Remarkable red shifts were observed in UVɃvis absorption spectra of multi-(phenylthio)porphyrinato Ni(ò) compounds which meet well with the electrochemical data. DFT calculation indicates that the phenylthio groups have strong effects on the frontier orbitals of these molecules. The order of a1u-like and a2u-like orbitals mainly distributed in porphyrin moiety is often inversed in energy when multi-phenylthio groups are attached.
2021, 32(8): 2567-2571
doi: 10.1016/j.cclet.2021.03.009
Abstract:
An N-heterocyclic carbene (NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-based β-hydroxyaldehyde has been developed. The ring opening-closure process enables the diastereodivergent synthesis of spirocyclopentaneoxindole products with four consecutive stereocenters by simply changing the reaction solvents (THF or DCE). The Michael/aldol/retro-aldol/aldol sequential protocol allows the diastereodivergent synthesis of spirocyclopentaneoxindoles from 3-substituted oxindole and α, β-unsaturated aldehyde under the relay catalysis of a chiral secondary amine and an NHC catalyst. Moreover, four stereoisomers of the product can be selectively provided by using different combinations of a chiral secondary amine and a solvent.
An N-heterocyclic carbene (NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-based β-hydroxyaldehyde has been developed. The ring opening-closure process enables the diastereodivergent synthesis of spirocyclopentaneoxindole products with four consecutive stereocenters by simply changing the reaction solvents (THF or DCE). The Michael/aldol/retro-aldol/aldol sequential protocol allows the diastereodivergent synthesis of spirocyclopentaneoxindoles from 3-substituted oxindole and α, β-unsaturated aldehyde under the relay catalysis of a chiral secondary amine and an NHC catalyst. Moreover, four stereoisomers of the product can be selectively provided by using different combinations of a chiral secondary amine and a solvent.
2021, 32(8): 2380-2384
doi: 10.1016/j.cclet.2021.02.065
Abstract:
Hydrogen sulfide (H2S) is a signaling molecule that plays important roles in biological systems. The exploration of H2S as a new drug release trigger and its related fluorescent theranostic system is crucial for cancer bio-imaging and therapy. Herein, we designed a new two-photon ratiometric fluorescent theranostic prodrug (compound 1) and studied its spectroscopic properties and application in in vivo imaging. Compound 1 specifically reacted with H2S and released the free active therapeutic component of 7-ethyl-10-hydroxycamptothecin, which was accompanied with a red-shift fluorescence emission signal from 460 nm to 545 nm. The exogenous and endogenous H2S in living cells were imaged by compound 1 under one-photon and two-photon excitation. Furthermore, compound 1 monitored the H2S concentration changes in Caenorhabditis elegans by fluorescence imaging. Additionally, it showed effective drug release activation in situ tumor with exogenous and endogenous H2S as the trigger. The H2S-sensitive activation and drug-release properties highlight the potential of theranostic compound 1 in future cancer treatment and therapy.
Hydrogen sulfide (H2S) is a signaling molecule that plays important roles in biological systems. The exploration of H2S as a new drug release trigger and its related fluorescent theranostic system is crucial for cancer bio-imaging and therapy. Herein, we designed a new two-photon ratiometric fluorescent theranostic prodrug (compound 1) and studied its spectroscopic properties and application in in vivo imaging. Compound 1 specifically reacted with H2S and released the free active therapeutic component of 7-ethyl-10-hydroxycamptothecin, which was accompanied with a red-shift fluorescence emission signal from 460 nm to 545 nm. The exogenous and endogenous H2S in living cells were imaged by compound 1 under one-photon and two-photon excitation. Furthermore, compound 1 monitored the H2S concentration changes in Caenorhabditis elegans by fluorescence imaging. Additionally, it showed effective drug release activation in situ tumor with exogenous and endogenous H2S as the trigger. The H2S-sensitive activation and drug-release properties highlight the potential of theranostic compound 1 in future cancer treatment and therapy.
2021, 32(8): 2385-2389
doi: 10.1016/j.cclet.2021.02.059
Abstract:
Lipid droplets (LDs) are intracellular lipid-metabolism organelles that involved in many physiological processes, metabolic disorders as well as diseases such as atherosclerosis. However, the specific probes that can visually locate abnormal LDs-rich tissues and track LDs-associated behavior to the naked eye with adequate biosafety still are rare. Herein, we develop a new design strategy of LDs-targeted probe based on the solvatochromism of coumarin derivatives. The results revealed that the emission wavelength of coumarin fluorophores gradually red shift in different solvents with increasing polarity, while absorption wavelength almost unchanged. As a result, the enlarged stokes shift of coumarin was emerged from oil to water. Furthermore, properly reducing water solubility and adding electronic donor at the structure of coumarins can enlarge this type of solvatochromism. This discovery was utilized to develop suitable probe for the image of LDs and LDs-rich tissues with high resolution and biosafety. Therefore, LDs-associated behavior was visible to the naked eye during the process of lipophagy and atherosclerosis. We deem that the developed probe here offers a new possibility to accurately diagnosis and analyse LDs-related diseases in clinic and preclinical study.
Lipid droplets (LDs) are intracellular lipid-metabolism organelles that involved in many physiological processes, metabolic disorders as well as diseases such as atherosclerosis. However, the specific probes that can visually locate abnormal LDs-rich tissues and track LDs-associated behavior to the naked eye with adequate biosafety still are rare. Herein, we develop a new design strategy of LDs-targeted probe based on the solvatochromism of coumarin derivatives. The results revealed that the emission wavelength of coumarin fluorophores gradually red shift in different solvents with increasing polarity, while absorption wavelength almost unchanged. As a result, the enlarged stokes shift of coumarin was emerged from oil to water. Furthermore, properly reducing water solubility and adding electronic donor at the structure of coumarins can enlarge this type of solvatochromism. This discovery was utilized to develop suitable probe for the image of LDs and LDs-rich tissues with high resolution and biosafety. Therefore, LDs-associated behavior was visible to the naked eye during the process of lipophagy and atherosclerosis. We deem that the developed probe here offers a new possibility to accurately diagnosis and analyse LDs-related diseases in clinic and preclinical study.
2021, 32(8): 2390-2394
doi: 10.1016/j.cclet.2021.02.037
Abstract:
The fascinating luminescence properties of gold nanoclusters (AuNCs) have drawn considerable research interests, and been widely harnessed for a wide range of applications. However, a fundamental understanding towards ligand density's role in the luminescence properties of these ultrasmall AuNCs remains unclear yet. In this communication, through systematic investigation of surface chemistries of glutathione-protected AuNCs (GSH-AuNCs) with different density of GSH as well as other thiolates, it is discovered that the density of surface ligands can significantly regulate the luminescence properties of AuNCs. Fluorescence lifetime spectroscopy and X-ray photoelectron spectroscopy showed that AuNCs with a higher density of electron-rich ligands facilitate their luminescence generation. Moreover, differences in the surface coverage of AuNCs can also affect their interactions with foreign species, as illustrated by significantly different fluorescence quenching capability of GSH-AuNCs with different ligand density towards Hg2+. This study provides new insight into the intriguing luminescence properties of metal NCs, which is hoped to stimulate further research on the design of metal NCs with strong luminescence and sensitive/specific responses for promising optoelectronic, sensing and imaging applications.
The fascinating luminescence properties of gold nanoclusters (AuNCs) have drawn considerable research interests, and been widely harnessed for a wide range of applications. However, a fundamental understanding towards ligand density's role in the luminescence properties of these ultrasmall AuNCs remains unclear yet. In this communication, through systematic investigation of surface chemistries of glutathione-protected AuNCs (GSH-AuNCs) with different density of GSH as well as other thiolates, it is discovered that the density of surface ligands can significantly regulate the luminescence properties of AuNCs. Fluorescence lifetime spectroscopy and X-ray photoelectron spectroscopy showed that AuNCs with a higher density of electron-rich ligands facilitate their luminescence generation. Moreover, differences in the surface coverage of AuNCs can also affect their interactions with foreign species, as illustrated by significantly different fluorescence quenching capability of GSH-AuNCs with different ligand density towards Hg2+. This study provides new insight into the intriguing luminescence properties of metal NCs, which is hoped to stimulate further research on the design of metal NCs with strong luminescence and sensitive/specific responses for promising optoelectronic, sensing and imaging applications.
2021, 32(8): 2395-2399
doi: 10.1016/j.cclet.2021.02.031
Abstract:
Here we propose a fluorescent sensor, Chroma-V, consisted of a Hoechst ligand (Hoe) to target chromatin DNA and a BODIPY rotor (BDP) to sense the local viscosity that reflects chromatin condensation state. Within Chroma-V, efficient FRET process from Hoe to BDP facilitated a single-excitation ratiometric imaging of nucleus DNA under fluorescence confocal microscope, which utilized the ratio of two channels to enable an intuitive visualization of chromatin condensation state. And fluorescence lifetime imaging (FLIM) based on fluorescent signal from BDP proved to be a more accurate method to quantify the changes of chromatin condensation state under different epigenetic states, including histone acetylation regulated by deacetylase inhibitors, cell apoptosis induced by DNA-bining drugs, and the epithelial-mesenchymal transition of HUVEC cells induced by TGF-β.
Here we propose a fluorescent sensor, Chroma-V, consisted of a Hoechst ligand (Hoe) to target chromatin DNA and a BODIPY rotor (BDP) to sense the local viscosity that reflects chromatin condensation state. Within Chroma-V, efficient FRET process from Hoe to BDP facilitated a single-excitation ratiometric imaging of nucleus DNA under fluorescence confocal microscope, which utilized the ratio of two channels to enable an intuitive visualization of chromatin condensation state. And fluorescence lifetime imaging (FLIM) based on fluorescent signal from BDP proved to be a more accurate method to quantify the changes of chromatin condensation state under different epigenetic states, including histone acetylation regulated by deacetylase inhibitors, cell apoptosis induced by DNA-bining drugs, and the epithelial-mesenchymal transition of HUVEC cells induced by TGF-β.
2021, 32(8): 2400-2404
doi: 10.1016/j.cclet.2021.02.060
Abstract:
Currently, architecting a rational and efficient nanoplatform combing with multi-therapeutic modalities is highly obligatory for advanced cancer treatment. In order to remedy the self-limiting hypoxic dilemma of photodynamic therapy (PDT), herein, a facile photosensitizer (i.e., chlorin e6, Ce6) and bioreductive prodrug (i.e., tirapazamine, TPZ)-coloaded hyaluronic acid (HA) nanomicelles (denoted as TPZ@HA-Ce6) was developed for the cascading mode of photo-bioreductive cancer therapy. Taking the typical advantage of Ce6 coupled HA conjugate, TPZ was easily and successfully accommodated into the hydrophobic core of HA-Ce6 nanomicelles, yielding TPZ@HA-Ce6. It showed good dispersibility and stability with the hydrodynamic size of ca. 170 nm. It targeted the CD44 overexpressed cancer cells by receptor-mediated endocytosis way and killed them effectively with singlet oxygen and the subsequent TPZ radicals resulting from the oxygen depletion of PDT. The later was further verified by the hypoxia probe in vivo. Using murine mammary carcinoma 4 T1 model, TPZ@HA-Ce6 nanomicelles exhibited cascading and synergistic anticancer effect of PDT and TPZ bioreductive therapy compared with each monotherapy. This work suggests the promising prospect of the hybrid hyaluronic nanomicelles for highly efficient cancer combination treatment.
Currently, architecting a rational and efficient nanoplatform combing with multi-therapeutic modalities is highly obligatory for advanced cancer treatment. In order to remedy the self-limiting hypoxic dilemma of photodynamic therapy (PDT), herein, a facile photosensitizer (i.e., chlorin e6, Ce6) and bioreductive prodrug (i.e., tirapazamine, TPZ)-coloaded hyaluronic acid (HA) nanomicelles (denoted as TPZ@HA-Ce6) was developed for the cascading mode of photo-bioreductive cancer therapy. Taking the typical advantage of Ce6 coupled HA conjugate, TPZ was easily and successfully accommodated into the hydrophobic core of HA-Ce6 nanomicelles, yielding TPZ@HA-Ce6. It showed good dispersibility and stability with the hydrodynamic size of ca. 170 nm. It targeted the CD44 overexpressed cancer cells by receptor-mediated endocytosis way and killed them effectively with singlet oxygen and the subsequent TPZ radicals resulting from the oxygen depletion of PDT. The later was further verified by the hypoxia probe in vivo. Using murine mammary carcinoma 4 T1 model, TPZ@HA-Ce6 nanomicelles exhibited cascading and synergistic anticancer effect of PDT and TPZ bioreductive therapy compared with each monotherapy. This work suggests the promising prospect of the hybrid hyaluronic nanomicelles for highly efficient cancer combination treatment.
2021, 32(8): 2405-2410
doi: 10.1016/j.cclet.2021.02.030
Abstract:
Developing low toxicity and multifunctional theranostic nanoplatform is the key for precise cancer diagnosis and treatment. Herein, an inorganic-organic hybrid nanocomposite is designed by modifying zirconium dioxide (ZrO2) with polydopamine (PDA) followed by doping Mn2+ ions and functionalizing with Tween 20 (Tween-ZrO2@PDA-Mn2+) for multimodal imaging and chemo-photothermal combination therapy. The as-prepared nanocomposite exhibits good biocompatibility in vitro and in vivo. Specifically, it can be employed as a multifunctional platform not only for computed tomography (CT) imaging and T1-weighted magnetic resonance (MR) imaging, but also for efficient chemotherapeutic drug doxorubicin hydrochloride (DOX) loading. Importantly, because of the pronounced photothermal conversion performance and controllable DOX release ability triggered by the near-infrared (NIR) irradiation and acidic pH, the synergistic effect between photothermal therapy and chemotherapy results in an enhanced cancer treatment efficacy in vivo. Our work provides a high-performance inorganic-organic hybrid nanotheranostic platform for chemo-photothermal cancer therapy guided by CT and MR imaging.
Developing low toxicity and multifunctional theranostic nanoplatform is the key for precise cancer diagnosis and treatment. Herein, an inorganic-organic hybrid nanocomposite is designed by modifying zirconium dioxide (ZrO2) with polydopamine (PDA) followed by doping Mn2+ ions and functionalizing with Tween 20 (Tween-ZrO2@PDA-Mn2+) for multimodal imaging and chemo-photothermal combination therapy. The as-prepared nanocomposite exhibits good biocompatibility in vitro and in vivo. Specifically, it can be employed as a multifunctional platform not only for computed tomography (CT) imaging and T1-weighted magnetic resonance (MR) imaging, but also for efficient chemotherapeutic drug doxorubicin hydrochloride (DOX) loading. Importantly, because of the pronounced photothermal conversion performance and controllable DOX release ability triggered by the near-infrared (NIR) irradiation and acidic pH, the synergistic effect between photothermal therapy and chemotherapy results in an enhanced cancer treatment efficacy in vivo. Our work provides a high-performance inorganic-organic hybrid nanotheranostic platform for chemo-photothermal cancer therapy guided by CT and MR imaging.
2021, 32(8): 2411-2414
doi: 10.1016/j.cclet.2021.03.080
Abstract:
Gold nanovesicles (GVs) with unique plasmonic property and large cavity hold great potential as a stimuli-responsive nanocarrier to deliver drugs for efficient tumor chemotherapy and other therapies synergistically. Herein, we developed doxorubicin-loaded gold nanovesicles (DGVs), offering infrared thermal (IRT) and photoacoustic (PA) dual-modal imaging guided mild hyperthermia-enhanced chemo-photothermal cancer synergistic therapy. The DGVs are self-assembled by gold nanoparticles modified with amphiphilic copolymer in a predetermined concentration of doxorubicin through film rehydration method. Under the influence of laser excitation, the as-prepared DGVs exhibited good photothermal effect, which triggered the structural disruption of GVs and thus, allowed the efficient release of encapsulated DOX to enhance cell uptake for fluorescence imaging and tumor chemotherapy, respectively. In addition, DGVs also showed a strong PA and IRT signals in vivo. Our study demonstrated the potential of DGVs as stimuli-responsive drug delivery systems and cancer theranostics.
Gold nanovesicles (GVs) with unique plasmonic property and large cavity hold great potential as a stimuli-responsive nanocarrier to deliver drugs for efficient tumor chemotherapy and other therapies synergistically. Herein, we developed doxorubicin-loaded gold nanovesicles (DGVs), offering infrared thermal (IRT) and photoacoustic (PA) dual-modal imaging guided mild hyperthermia-enhanced chemo-photothermal cancer synergistic therapy. The DGVs are self-assembled by gold nanoparticles modified with amphiphilic copolymer in a predetermined concentration of doxorubicin through film rehydration method. Under the influence of laser excitation, the as-prepared DGVs exhibited good photothermal effect, which triggered the structural disruption of GVs and thus, allowed the efficient release of encapsulated DOX to enhance cell uptake for fluorescence imaging and tumor chemotherapy, respectively. In addition, DGVs also showed a strong PA and IRT signals in vivo. Our study demonstrated the potential of DGVs as stimuli-responsive drug delivery systems and cancer theranostics.
2021, 32(8): 2415-2418
doi: 10.1016/j.cclet.2021.01.010
Abstract:
Supramolecular transformations of coordination cage or capsule have received much attention recently, which help elucidate this natural self-assembly behavior in biological systems. The current study describes the first supramolecular transformation of titanium–organic coordination capsule triggered by phenol (and H3PO3). The structural alterations are accompanied by the reconstruction of 5-coordinated Ti centers to 6-coordinated ones. Meanwhile, different amounts of encapsulated phenol guest molecules can be identified, dependent on the sizes of the obtained cavities. In addition, they display much better visible light absorption and air stability than the isopropanol stabilized ones.
Supramolecular transformations of coordination cage or capsule have received much attention recently, which help elucidate this natural self-assembly behavior in biological systems. The current study describes the first supramolecular transformation of titanium–organic coordination capsule triggered by phenol (and H3PO3). The structural alterations are accompanied by the reconstruction of 5-coordinated Ti centers to 6-coordinated ones. Meanwhile, different amounts of encapsulated phenol guest molecules can be identified, dependent on the sizes of the obtained cavities. In addition, they display much better visible light absorption and air stability than the isopropanol stabilized ones.
2021, 32(8): 2419-2422
doi: 10.1016/j.cclet.2021.01.013
Abstract:
Owing to excellent light absorption and high activity for oxygen evolution, monoclinic bismuth vanadate (BiVO4) is regarded as an ideal candidate for photocatalytic water splitting. However, its application is limited by the large particle size in micrometer scale, as well as the slightly positive conduction band. In this work, we successfully synthesized nano-BiVO4 with particle size ranged from 27 nm to 57 nm by wet chemical method based on electrostatic spinning method. Unlike bulk BiVO4, the nano-sized BiVO4 possesses the ability to generate hydrogen by water splitting, and the activity could reach up to 1.66 μmol h−1g−1 with the assistance of Pt. The enhanced activity is mainly attributed to the improvements resulted from reduced particle size, which includes elevated conduction band, enlarged specific surface area and promoted charge separation. This work provides a simple method for synthesizing photocatalyst with small particle size and high yield.
Owing to excellent light absorption and high activity for oxygen evolution, monoclinic bismuth vanadate (BiVO4) is regarded as an ideal candidate for photocatalytic water splitting. However, its application is limited by the large particle size in micrometer scale, as well as the slightly positive conduction band. In this work, we successfully synthesized nano-BiVO4 with particle size ranged from 27 nm to 57 nm by wet chemical method based on electrostatic spinning method. Unlike bulk BiVO4, the nano-sized BiVO4 possesses the ability to generate hydrogen by water splitting, and the activity could reach up to 1.66 μmol h−1g−1 with the assistance of Pt. The enhanced activity is mainly attributed to the improvements resulted from reduced particle size, which includes elevated conduction band, enlarged specific surface area and promoted charge separation. This work provides a simple method for synthesizing photocatalyst with small particle size and high yield.
2021, 32(8): 2423-2426
doi: 10.1016/j.cclet.2021.01.015
Abstract:
In the crystal engineering area, it is important to clearly demonstrating the relationship of structure and certain functionality. Herein, we present the study of the relationship of structure with phosphorescent nature for two new room temperature phosphorescence (RTP) coordination polymers (CPs). [Pb(FDA)(H2O)] (1) and [NH3(CH3)NH2(CH3)2][Pb4(FDA)5] (2), where H2FDA is 2, 5-furandicarboxylic acid, have been synthesized by solvothermal method using different solvents and Pb2+ sources and characterized by microanalysis, powder X-ray diffraction (PXRD), thermogravimetric (TG), IR and UV–vis spectra. The Pb2+ ions adopt bicapped triangle prism coordination sphere in 1 and 2, which are connected together via FDA2− ligands into bilayer structure in 1 while pillared-layer framework in 2. The FDA2− ligands show different bridging modes in 1 and 2, leading to distinct coordination interactions between Pb2+ ion and FDA2− ligand in both CPs. Both 1 and 2 emit ligand-centered RTP due to the heavy atom of Pb2+ ion, with a lifetime and quantum yield of 0.62 ms and 14.9% in 1 versus 1.69 ms and 15.7% in 2. The emission peak shows significant redshift (79 nm) in 2 regarding 1, which arises from their distinction of coordination interactions between Pb2+ ion and FDA2− ligand in both CPs.
In the crystal engineering area, it is important to clearly demonstrating the relationship of structure and certain functionality. Herein, we present the study of the relationship of structure with phosphorescent nature for two new room temperature phosphorescence (RTP) coordination polymers (CPs). [Pb(FDA)(H2O)] (1) and [NH3(CH3)NH2(CH3)2][Pb4(FDA)5] (2), where H2FDA is 2, 5-furandicarboxylic acid, have been synthesized by solvothermal method using different solvents and Pb2+ sources and characterized by microanalysis, powder X-ray diffraction (PXRD), thermogravimetric (TG), IR and UV–vis spectra. The Pb2+ ions adopt bicapped triangle prism coordination sphere in 1 and 2, which are connected together via FDA2− ligands into bilayer structure in 1 while pillared-layer framework in 2. The FDA2− ligands show different bridging modes in 1 and 2, leading to distinct coordination interactions between Pb2+ ion and FDA2− ligand in both CPs. Both 1 and 2 emit ligand-centered RTP due to the heavy atom of Pb2+ ion, with a lifetime and quantum yield of 0.62 ms and 14.9% in 1 versus 1.69 ms and 15.7% in 2. The emission peak shows significant redshift (79 nm) in 2 regarding 1, which arises from their distinction of coordination interactions between Pb2+ ion and FDA2− ligand in both CPs.
2021, 32(8): 2427-2432
doi: 10.1016/j.cclet.2021.01.022
Abstract:
Developing high-efficiency, inexpensive, and steady non-precious metal oxygen reduction reaction (ORR) catalysts to displace Pt-based catalysts is significant for commercial applications of Al-air battery. Here, we have prepared the Cu/Cu2O-NC catalyst with excellent ORR performance and high stability, due to the synergistic effect of Cu and Cu2O nanoparticles. The half-wave potential (0.8 V) and the limiting-current density (5.20 mA/cm2) of the Cu/Cu2O-NC are very close to those of the 20% Pt/C catalyst (0.82 V, 5.10 mA/cm2). Besides, it exhibits excellent performance with a maximal power density of 250 mW/cm2 and a stable continuous discharge for more than 90 h in the Al-air battery test. The promoting effects of Cu2O towards Cu-based ORR catalysts are illustrated as follows: (i) Cu2O is the major ORR active site by the redox of Cu(Ⅱ)/Cu(Ⅰ), which provides excellent ORR activities; (ii) Cu can stabilize the location of Cu2O by assisting the electron transfer to Cu(Ⅱ)/Cu(Ⅰ) redox, which is conducive to the high stability of the catalyst. This work provides a useful strategy for enhancing the ORR performance of Cu-based catalysts.
Developing high-efficiency, inexpensive, and steady non-precious metal oxygen reduction reaction (ORR) catalysts to displace Pt-based catalysts is significant for commercial applications of Al-air battery. Here, we have prepared the Cu/Cu2O-NC catalyst with excellent ORR performance and high stability, due to the synergistic effect of Cu and Cu2O nanoparticles. The half-wave potential (0.8 V) and the limiting-current density (5.20 mA/cm2) of the Cu/Cu2O-NC are very close to those of the 20% Pt/C catalyst (0.82 V, 5.10 mA/cm2). Besides, it exhibits excellent performance with a maximal power density of 250 mW/cm2 and a stable continuous discharge for more than 90 h in the Al-air battery test. The promoting effects of Cu2O towards Cu-based ORR catalysts are illustrated as follows: (i) Cu2O is the major ORR active site by the redox of Cu(Ⅱ)/Cu(Ⅰ), which provides excellent ORR activities; (ii) Cu can stabilize the location of Cu2O by assisting the electron transfer to Cu(Ⅱ)/Cu(Ⅰ) redox, which is conducive to the high stability of the catalyst. This work provides a useful strategy for enhancing the ORR performance of Cu-based catalysts.
2021, 32(8): 2433-2437
doi: 10.1016/j.cclet.2021.01.025
Abstract:
Prussian whites (PWs) with a three-dimensional framework can accommodate the insertion and extraction of ions with large radius, which have been widely used in potassium ion batteries. However, PWs show the poor cycling performance and inferior rate ability because of high coordinated water. In this work, PWs with different water content were synthesized via a coprecipitation method by controlling the reaction temperature. The sample with low-coordination water prohibits the best electrochemical performance. It shows a high capacity of 120.5 mAh/g at 100 mA/g for potassium-ion batteries (KIBs). It also exhibits a good rate performance, displaying a capacity of 73.2 mAh/g at 500 mA/g.
Prussian whites (PWs) with a three-dimensional framework can accommodate the insertion and extraction of ions with large radius, which have been widely used in potassium ion batteries. However, PWs show the poor cycling performance and inferior rate ability because of high coordinated water. In this work, PWs with different water content were synthesized via a coprecipitation method by controlling the reaction temperature. The sample with low-coordination water prohibits the best electrochemical performance. It shows a high capacity of 120.5 mAh/g at 100 mA/g for potassium-ion batteries (KIBs). It also exhibits a good rate performance, displaying a capacity of 73.2 mAh/g at 500 mA/g.
2021, 32(8): 2438-2442
doi: 10.1016/j.cclet.2021.02.010
Abstract:
Li-O2 batteries (LOBs) have been perceived as the most potential clean energy system for fast-growing electric vehicles by reason of their environmentally friendlier, high energy density and high reversibility. However, there are still some issues limiting the practical application of LOBs, such as the large gap between the actual capacity level and the theoretical capacity, low rate performance as well as short cycle life. Herein, hollow CeO2/Co3O4 polyhedrons have been synthesized by MOF template with a simple method. And it is was further served as a cathode catalyst in Li-O2 batteries. By means of the synergistic effect of two different transition metal oxides, nano-sized hollow porous CeO2/Co3O4 cathode obtained better capacity and cycle performance. As a result, excellent cyclability of exceeding 140 and 90 cycles are achieved at a fixed capacity of 600 and 1000 mAh/g, respectively. The successful application of this catalyst in LOBs offers a novel route in the aspect of the synthesis of other hollow porous composite oxides as catalysts for cathodes in LOBs systems by the MOF template method.
Li-O2 batteries (LOBs) have been perceived as the most potential clean energy system for fast-growing electric vehicles by reason of their environmentally friendlier, high energy density and high reversibility. However, there are still some issues limiting the practical application of LOBs, such as the large gap between the actual capacity level and the theoretical capacity, low rate performance as well as short cycle life. Herein, hollow CeO2/Co3O4 polyhedrons have been synthesized by MOF template with a simple method. And it is was further served as a cathode catalyst in Li-O2 batteries. By means of the synergistic effect of two different transition metal oxides, nano-sized hollow porous CeO2/Co3O4 cathode obtained better capacity and cycle performance. As a result, excellent cyclability of exceeding 140 and 90 cycles are achieved at a fixed capacity of 600 and 1000 mAh/g, respectively. The successful application of this catalyst in LOBs offers a novel route in the aspect of the synthesis of other hollow porous composite oxides as catalysts for cathodes in LOBs systems by the MOF template method.
2021, 32(8): 2443-2447
doi: 10.1016/j.cclet.2021.01.040
Abstract:
We herein report a new lanthanide metal-organic framework (MOF) that exhibits excellent chemical stability, especially in the aqueous solution over a wide pH range from 1 to 14. In contrast to many reported lanthanide MOFs, this Tb-based MOF emits cyan fluorescence inherited from the integrated AIE-active ligand, rather than Ln3+ ions. More remarkably, its fluorescence signal features a highly selective and sensitive "turn-off" response toward CrO42−, Cr2O72− and Fe3+ ions, highlighted with the low detection limits down to 68.18, 69.85 and 138.8 ppm, respectively. Thus, the exceptional structural stability and sensing performance render this material able to be a superior luminescent sensor for heavy metal ions in wastewater.
We herein report a new lanthanide metal-organic framework (MOF) that exhibits excellent chemical stability, especially in the aqueous solution over a wide pH range from 1 to 14. In contrast to many reported lanthanide MOFs, this Tb-based MOF emits cyan fluorescence inherited from the integrated AIE-active ligand, rather than Ln3+ ions. More remarkably, its fluorescence signal features a highly selective and sensitive "turn-off" response toward CrO42−, Cr2O72− and Fe3+ ions, highlighted with the low detection limits down to 68.18, 69.85 and 138.8 ppm, respectively. Thus, the exceptional structural stability and sensing performance render this material able to be a superior luminescent sensor for heavy metal ions in wastewater.
2021, 32(8): 2448-2452
doi: 10.1016/j.cclet.2021.01.043
Abstract:
Carbon nanofiber-based supercapacitors have broad prospects in powering wearable electronics owing to their high specific capacity, fast charge/discharge process, along with long-cycling life. Herein, a poly(acrylonitrile-co-β-methylhydrogen itaconate) copolymer was prepared and used to synthesize flexible hollow carbon nanofibers (HCNFs) via an electrospinning method without breaking after multiple bending. Subsequently, the inner and outer surfaces of HCNFs were evenly covered with ordered needle-like polyaniline (PANI) through in-situ polymerization methods to obtain three-dimensional flexible HCNFs/PANI composites, which exhibited a high capacity 1196.7 F/g at 1 A/g and good cycling stability (90.1% retention at 5 A/g after 3000 cycles). The symmetrical supercapacitor based on the HCNFs/PANI composites also delivered an outstanding electrochemical performance with high energy/power density (60.28 Wh/kg at 1000 W/kg) and superior cycling durability (90% capacitance retention after at 5 A/g 3000 cycles), which confirmed that the HCNFs/PANI composites had a wide application potential in flexible energy storage devices.
Carbon nanofiber-based supercapacitors have broad prospects in powering wearable electronics owing to their high specific capacity, fast charge/discharge process, along with long-cycling life. Herein, a poly(acrylonitrile-co-β-methylhydrogen itaconate) copolymer was prepared and used to synthesize flexible hollow carbon nanofibers (HCNFs) via an electrospinning method without breaking after multiple bending. Subsequently, the inner and outer surfaces of HCNFs were evenly covered with ordered needle-like polyaniline (PANI) through in-situ polymerization methods to obtain three-dimensional flexible HCNFs/PANI composites, which exhibited a high capacity 1196.7 F/g at 1 A/g and good cycling stability (90.1% retention at 5 A/g after 3000 cycles). The symmetrical supercapacitor based on the HCNFs/PANI composites also delivered an outstanding electrochemical performance with high energy/power density (60.28 Wh/kg at 1000 W/kg) and superior cycling durability (90% capacitance retention after at 5 A/g 3000 cycles), which confirmed that the HCNFs/PANI composites had a wide application potential in flexible energy storage devices.
2021, 32(8): 2453-2458
doi: 10.1016/j.cclet.2021.01.042
Abstract:
In power storage technology, ion exchange is widely used to modify the electronic structures of electrode materials to stimulate their electrochemical properties. Here, we proposed a multistep ion exchange (cation exchange and anion exchange) strategy to synthesize amorphous Ni-Co-S and β-Co(OH)2 hybrid nanomaterials with a hollow polyhedron structures. The synergistic effects of different components and the remarkable superiorities of hollow structure endow Ni-Co-S/Co(OH)2 electrode with outstanding electrochemical performance, including ultra-high specific capacity (1440.0 C/g at 1 A/g), superior capacitance retention rate (79.1% retention at 20 A/g) and long operating lifespan (81.4% retention after 5000 cycles). Moreover, the corresponding hybrid supercapacitor enjoys a high energy density of 58.4 Wh/kg at the power density of 0.8 kW/kg, and a decent cyclability that the capacitances are maintained at 80.8% compared with the initial capacitance. This research presents a high-performance electrode material and provides a promising route for the construction of electrode materials for supercapacitors with both structural and component advantages.
In power storage technology, ion exchange is widely used to modify the electronic structures of electrode materials to stimulate their electrochemical properties. Here, we proposed a multistep ion exchange (cation exchange and anion exchange) strategy to synthesize amorphous Ni-Co-S and β-Co(OH)2 hybrid nanomaterials with a hollow polyhedron structures. The synergistic effects of different components and the remarkable superiorities of hollow structure endow Ni-Co-S/Co(OH)2 electrode with outstanding electrochemical performance, including ultra-high specific capacity (1440.0 C/g at 1 A/g), superior capacitance retention rate (79.1% retention at 20 A/g) and long operating lifespan (81.4% retention after 5000 cycles). Moreover, the corresponding hybrid supercapacitor enjoys a high energy density of 58.4 Wh/kg at the power density of 0.8 kW/kg, and a decent cyclability that the capacitances are maintained at 80.8% compared with the initial capacitance. This research presents a high-performance electrode material and provides a promising route for the construction of electrode materials for supercapacitors with both structural and component advantages.
2021, 32(8): 2459-2462
doi: 10.1016/j.cclet.2021.01.049
Abstract:
Bi draws increasing attention as anode materials for lithium-ion batteries and sodium-ion batteries due to its unique layered crystal structure, which is in favor of achieving fast ionic diffusion kinetics during cycling. However, the dramatic volume expansion upon lithiation/sodiation and an insufficient theoretical capacity of Bi greatly hinder its practical application. Herein, we report the Fe2O3 nanoparticle-pinning Bi-encapsulated carbon fiber composites through the electrospinning technique. The introduction of Fe2O3 nanoparticles can prevent the growth and aggregation of Bi nanoparticles during synthetic and cycling processes, respectively. Fe2O3 with high specific capacity also contributes to the specific capacity of the composites. Consequently, the as-prepared Bi-Fe2O3/carbon fiber composite exhibits outstanding long-term stability, which delivers reversible capacities 504 and 175 mAh/g after 1000 cycles at 1 A/g for lithium-ion and sodium-ion batteries, respectively.
Bi draws increasing attention as anode materials for lithium-ion batteries and sodium-ion batteries due to its unique layered crystal structure, which is in favor of achieving fast ionic diffusion kinetics during cycling. However, the dramatic volume expansion upon lithiation/sodiation and an insufficient theoretical capacity of Bi greatly hinder its practical application. Herein, we report the Fe2O3 nanoparticle-pinning Bi-encapsulated carbon fiber composites through the electrospinning technique. The introduction of Fe2O3 nanoparticles can prevent the growth and aggregation of Bi nanoparticles during synthetic and cycling processes, respectively. Fe2O3 with high specific capacity also contributes to the specific capacity of the composites. Consequently, the as-prepared Bi-Fe2O3/carbon fiber composite exhibits outstanding long-term stability, which delivers reversible capacities 504 and 175 mAh/g after 1000 cycles at 1 A/g for lithium-ion and sodium-ion batteries, respectively.
2021, 32(8): 2463-2468
doi: 10.1016/j.cclet.2021.03.017
Abstract:
Ion-in-conjugation (IIC) materials are emerging as an important class of organic electronic materials with wide applications in energy storage, resistive memories and gas sensors. Many IIC materials were designed and investigated, however the role of conjugation in IIC materials' performance is yet investigated. Here we designed two molecules obtained by condensation of 4-butylaniline and oxocarbon acid. Squaric acid derivatives squaraine named SA-Bu and a croconamide named CA-Bu which only differ in their oxocarbon cores. While employing SA-Bu and CA-Bu as resistive memory and gas sensory materials, SA-Bu has attained promising performance in ternary memory and detection of NO2 as low as 10 parts-per-billion whereas CA-Bu show mainly binary memory behavior and negligible NO2 response. Theoretical calculations reveal that conjugation of CA-Bu was distorted by the increased steric hindrance, frustrating the charge transport and suppressing the conductivity. Our work demonstrates that the conjugation plays a crucial role in ion-in-materials promoting ternary RRAM devices and high-performance gas sensors manufacture.
Ion-in-conjugation (IIC) materials are emerging as an important class of organic electronic materials with wide applications in energy storage, resistive memories and gas sensors. Many IIC materials were designed and investigated, however the role of conjugation in IIC materials' performance is yet investigated. Here we designed two molecules obtained by condensation of 4-butylaniline and oxocarbon acid. Squaric acid derivatives squaraine named SA-Bu and a croconamide named CA-Bu which only differ in their oxocarbon cores. While employing SA-Bu and CA-Bu as resistive memory and gas sensory materials, SA-Bu has attained promising performance in ternary memory and detection of NO2 as low as 10 parts-per-billion whereas CA-Bu show mainly binary memory behavior and negligible NO2 response. Theoretical calculations reveal that conjugation of CA-Bu was distorted by the increased steric hindrance, frustrating the charge transport and suppressing the conductivity. Our work demonstrates that the conjugation plays a crucial role in ion-in-materials promoting ternary RRAM devices and high-performance gas sensors manufacture.
2021, 32(8): 2469-2473
doi: 10.1016/j.cclet.2021.02.011
Abstract:
CO2 capture is considered as one of the most ideal strategies for solving the environmental issues and against global warming. Recently, experimental evidence has suggested that aluminum double bond (dialumene) species can capture CO2 and further convert it into value-added products. However, the catalytic application of these species is still in its infancy. Both the dynamics mechanism of CO2 fixation and the detailed structures of catalytic intermediates are not well understood. In this work, we investigate the structure dependent resonance Raman (RR) signals for different reaction intermediates. Ab-initio simulations of spontaneous resonance Raman (spRR) and time-domain stimulated resonance Raman (stRR) give spectral signatures correlated to the existence of different intermediates during the CO2-dialumene binding process. The unique Raman vibronic features contain rich structural information with high temporal resolution, enabling to monitor the transient catalytic intermediates under reaction conditions. Our work shows that RR can be used to monitor intermediates during the dialumene based CO2 capture reaction. The spectral features not only provide insight into the structural information of intermediate species, but also allow a deeper understanding of the dynamical details of this kind of catalytic process.
CO2 capture is considered as one of the most ideal strategies for solving the environmental issues and against global warming. Recently, experimental evidence has suggested that aluminum double bond (dialumene) species can capture CO2 and further convert it into value-added products. However, the catalytic application of these species is still in its infancy. Both the dynamics mechanism of CO2 fixation and the detailed structures of catalytic intermediates are not well understood. In this work, we investigate the structure dependent resonance Raman (RR) signals for different reaction intermediates. Ab-initio simulations of spontaneous resonance Raman (spRR) and time-domain stimulated resonance Raman (stRR) give spectral signatures correlated to the existence of different intermediates during the CO2-dialumene binding process. The unique Raman vibronic features contain rich structural information with high temporal resolution, enabling to monitor the transient catalytic intermediates under reaction conditions. Our work shows that RR can be used to monitor intermediates during the dialumene based CO2 capture reaction. The spectral features not only provide insight into the structural information of intermediate species, but also allow a deeper understanding of the dynamical details of this kind of catalytic process.
2021, 32(8): 2474-2478
doi: 10.1016/j.cclet.2021.01.004
Abstract:
Fabrication of well-designed heterojunctions is an extraordinarily attractive pathway for boosting the photocatalytic activity toward CO2 photoreduction. Herein, a novel kind of nanosheet-based intercalation hybrid coupled with CdSe quantum dots (QDs) was successfully fabricated by a facile solvothermal method and served as photocatalyst for full-spectrum-light-driven CO2 reduction. Ultra-small CdSe QDs were rationally in-situ introduced and coupled with lamellar ZnSe-intercalation hybrid nanosheet, resulting in the formation of CdSe QDs/ZnSe hybrid heterojunction. Significantly, the concentration of Cd2+ could change directly the crystallinity and micromorphology of ZnSe intercalation hybrid, which in turn would impact on the photocatalysis activity. The optimized CdSe QDs/ZnSe hybrid-5 composite demonstrated a considerable CO yield rate of the 25.6 μmol g-1 h-1 without any additional cocatalysts or sacrificial agents assisting, making it one of the best reported performance toward CO2 photoreduction under full-spectrum light. The elevated CO2 photoreduction activity could be attributed to the special surface heterojunction, leading to improving the ability of light absorption and promoting the separation/transfer of photogenerated carriers. This present study developed a new strategy for designing inorganic-organic heterojunctions with enhanced photocatalyst for CO2 photoreduction and provided an available way to simultaneously mitigate the greenhouse effect and alleviate energy shortage pressure.
Fabrication of well-designed heterojunctions is an extraordinarily attractive pathway for boosting the photocatalytic activity toward CO2 photoreduction. Herein, a novel kind of nanosheet-based intercalation hybrid coupled with CdSe quantum dots (QDs) was successfully fabricated by a facile solvothermal method and served as photocatalyst for full-spectrum-light-driven CO2 reduction. Ultra-small CdSe QDs were rationally in-situ introduced and coupled with lamellar ZnSe-intercalation hybrid nanosheet, resulting in the formation of CdSe QDs/ZnSe hybrid heterojunction. Significantly, the concentration of Cd2+ could change directly the crystallinity and micromorphology of ZnSe intercalation hybrid, which in turn would impact on the photocatalysis activity. The optimized CdSe QDs/ZnSe hybrid-5 composite demonstrated a considerable CO yield rate of the 25.6 μmol g-1 h-1 without any additional cocatalysts or sacrificial agents assisting, making it one of the best reported performance toward CO2 photoreduction under full-spectrum light. The elevated CO2 photoreduction activity could be attributed to the special surface heterojunction, leading to improving the ability of light absorption and promoting the separation/transfer of photogenerated carriers. This present study developed a new strategy for designing inorganic-organic heterojunctions with enhanced photocatalyst for CO2 photoreduction and provided an available way to simultaneously mitigate the greenhouse effect and alleviate energy shortage pressure.
2021, 32(8): 2479-2483
doi: 10.1016/j.cclet.2021.02.004
Abstract:
DNA methyltransferase (DNMT) and histone deacetylase (HDAC) are well recognized epigenetic targets for discovery of antitumor agents. In this study, we designed and synthesized a series of nucleoside base hydroxamic acid derivatives as DNMT and HDAC dual inhibitors. MTT assays and enzymatic inhibitory activity tests indicated that compound 204 exhibited potent DNMT1 and HDAC1/6 inhibitory potency simultaneously in enzymatic levels and at cellular levels, inducing hypomethylation of p16 and hyperacetylation of histones H3K9 and H4K8. Besides, 204 remarkably inhibited proliferation against cancer cells U937 by prompting G0/G1 cell cycle arrest. Molecular docking models explained the functional mechanism of 204 inhibiting DNMT1 and HDAC. Preliminary studies on metabolic profiles revealed that 204 showed desirable stability in liver microsomes. Our study suggested that 204 inhibiting DNMT and HDAC concurrently can be a potential lead compound for epigenetic cancer therapy.
DNA methyltransferase (DNMT) and histone deacetylase (HDAC) are well recognized epigenetic targets for discovery of antitumor agents. In this study, we designed and synthesized a series of nucleoside base hydroxamic acid derivatives as DNMT and HDAC dual inhibitors. MTT assays and enzymatic inhibitory activity tests indicated that compound 204 exhibited potent DNMT1 and HDAC1/6 inhibitory potency simultaneously in enzymatic levels and at cellular levels, inducing hypomethylation of p16 and hyperacetylation of histones H3K9 and H4K8. Besides, 204 remarkably inhibited proliferation against cancer cells U937 by prompting G0/G1 cell cycle arrest. Molecular docking models explained the functional mechanism of 204 inhibiting DNMT1 and HDAC. Preliminary studies on metabolic profiles revealed that 204 showed desirable stability in liver microsomes. Our study suggested that 204 inhibiting DNMT and HDAC concurrently can be a potential lead compound for epigenetic cancer therapy.
2021, 32(8): 2484-2488
doi: 10.1016/j.cclet.2020.12.045
Abstract:
Electrochemical water splitting is a facile and effective route to generate pure hydrogen and oxygen. However, the sluggish kinetics of hydrogen evolution reaction (HER) and especially oxygen evolution reaction (OER) hinder the water splitting efficiency. Meanwhile, the high-cost of noble-metal catalysts limit their actual application. It is thus highly urgent to exploit an economical and earth-abundant bifunctional HER and OER electrocatalyst to simplify procedure and reduce cost. Herein, we synthesize the three-dimensionally ordered macro-/mesoporous (3DOM/m) NixCo100-x alloys with distinctive structure and large surface area via a dual-templating technique. Among them, the 3DOM/m Ni61Co39 shows the lowest overpotentials of 121 mV and 241 mV at 10 mA/cm2 for HER and OER, respectively. Furthermore, when employed for water splitting, the Ni61Co39 only requires 1.60 V to approach 10 mA/cm2 and presents excellent stability. These encouraging performances of the Ni61Co39 render it a promising bifunctional catalyst for overall water splitting.
Electrochemical water splitting is a facile and effective route to generate pure hydrogen and oxygen. However, the sluggish kinetics of hydrogen evolution reaction (HER) and especially oxygen evolution reaction (OER) hinder the water splitting efficiency. Meanwhile, the high-cost of noble-metal catalysts limit their actual application. It is thus highly urgent to exploit an economical and earth-abundant bifunctional HER and OER electrocatalyst to simplify procedure and reduce cost. Herein, we synthesize the three-dimensionally ordered macro-/mesoporous (3DOM/m) NixCo100-x alloys with distinctive structure and large surface area via a dual-templating technique. Among them, the 3DOM/m Ni61Co39 shows the lowest overpotentials of 121 mV and 241 mV at 10 mA/cm2 for HER and OER, respectively. Furthermore, when employed for water splitting, the Ni61Co39 only requires 1.60 V to approach 10 mA/cm2 and presents excellent stability. These encouraging performances of the Ni61Co39 render it a promising bifunctional catalyst for overall water splitting.
2021, 32(8): 2489-2494
doi: 10.1016/j.cclet.2020.12.057
Abstract:
Different from traditional metal-support heterogenous catalysts, inverse heterogeneous catalysts, in which the surface of metal is decorated by metal oxide, have recently attracted increasing interests owing to the unique interfacial effect and electronic structure. However, a deep insight into the effect of metal-oxide interaction on the catalytic performance still remains a great challenge. In our work, an inverse hematite/palladium (Fe2O3/Pd) hybrid nanostructure, i.e., the active Fe2O3 ultrathin oxide layers partially covering on the surface of Pd nanoparticles (NPs), exhibited superior electrocatalytic performance towards methanol oxidation reaction (MOR) as compared to the bare Pd NPs based on density functional theory calculation. The charge could transfer from Pd to Fe2O3 driven by the built-in potential at the interface of Pd and Fe2O3, which favors the downshift of d band center of Pd. With the assistance of interfacial hydroxyl OH*, the cleavage of OH and CH in CH3OH could take place much easily with lower barrier energy on Fe2O3/Pd than that on pure Pd via two electrons transferring reaction pathways. Our results highlight that the synergy of Pd and Fe2O3 at the interface could facilitate the electrochemical transformation of methanol into formaldehyde assisted with interfacial hydroxyl OH*.
Different from traditional metal-support heterogenous catalysts, inverse heterogeneous catalysts, in which the surface of metal is decorated by metal oxide, have recently attracted increasing interests owing to the unique interfacial effect and electronic structure. However, a deep insight into the effect of metal-oxide interaction on the catalytic performance still remains a great challenge. In our work, an inverse hematite/palladium (Fe2O3/Pd) hybrid nanostructure, i.e., the active Fe2O3 ultrathin oxide layers partially covering on the surface of Pd nanoparticles (NPs), exhibited superior electrocatalytic performance towards methanol oxidation reaction (MOR) as compared to the bare Pd NPs based on density functional theory calculation. The charge could transfer from Pd to Fe2O3 driven by the built-in potential at the interface of Pd and Fe2O3, which favors the downshift of d band center of Pd. With the assistance of interfacial hydroxyl OH*, the cleavage of OH and CH in CH3OH could take place much easily with lower barrier energy on Fe2O3/Pd than that on pure Pd via two electrons transferring reaction pathways. Our results highlight that the synergy of Pd and Fe2O3 at the interface could facilitate the electrochemical transformation of methanol into formaldehyde assisted with interfacial hydroxyl OH*.
2021, 32(8): 2495-2498
doi: 10.1016/j.cclet.2020.12.063
Abstract:
Morphology and dispersity are key factors for activating peroxymonosulfate (PMS). In this study, we designed a recyclable open-type NiCo2O4 hollow microsphere via a simple hydrothermal method with the assistance of an NH3 vesicle. The physical structure and chemical properties were characterized using techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), N2 adsorption and X-ray photoelectron spectroscopy (XPS). The test results confirm that the inner and outer surfaces of open-type NiCo2O4 hollow-sphere can be efficiently utilized because of the hole on the surface of the catalyst, which can minimize the diffusion resistance of the reactants and products. Under optimized conditions, the total organic carbon (TOC) removal efficiency of rhodamine B (RhB) can reach up to 80% in 40 min, which is almost 50% shorter than the reported values. The reactive radicals were identified and the proposed reaction mechanism was well described. Moreover, the disturbances of HCO3−, NO3−, Cl− and H2PO4− were further investigated. As a result, HCO3− and NO3− suppressed the reaction while Cl− and H2PO4− had a double effect on reaction.
Morphology and dispersity are key factors for activating peroxymonosulfate (PMS). In this study, we designed a recyclable open-type NiCo2O4 hollow microsphere via a simple hydrothermal method with the assistance of an NH3 vesicle. The physical structure and chemical properties were characterized using techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), N2 adsorption and X-ray photoelectron spectroscopy (XPS). The test results confirm that the inner and outer surfaces of open-type NiCo2O4 hollow-sphere can be efficiently utilized because of the hole on the surface of the catalyst, which can minimize the diffusion resistance of the reactants and products. Under optimized conditions, the total organic carbon (TOC) removal efficiency of rhodamine B (RhB) can reach up to 80% in 40 min, which is almost 50% shorter than the reported values. The reactive radicals were identified and the proposed reaction mechanism was well described. Moreover, the disturbances of HCO3−, NO3−, Cl− and H2PO4− were further investigated. As a result, HCO3− and NO3− suppressed the reaction while Cl− and H2PO4− had a double effect on reaction.
2021, 32(8): 2499-2502
doi: 10.1016/j.cclet.2020.12.048
Abstract:
Microbial fuel cells (MFCs) have various potential applications. However, anode is a main bottleneck that limits electricity production performance of MFCs. Herein, we developed a novel anode based on a stainless steel cloth (SC) modified with carbon nanoparticles of Chinese ink (CI) using polypyrrole (PPy) as a building block (PPy/CI/SC). After modification, PPy/CI/SC showed a 30% shorten in start-up time (36.4 ± 3.3 h vs. 52.3 ± 1.8 h), 33% increase in the maximum current (12.4 ± 1.4 mA vs. 9.3 ± 0.95 mA), and 2.3 times higher in the maximum power density of MFC (61.9 mW/m2 vs. 27.3 mW/m2), compared to Ppy/SC. Experimental results revealed that carbon nanoparticles were able to cover SC uniformly, owing to excellent dispersibility of carbon nanoparticles in CI. The attachment of carbon nanoparticles formed a fluffy layer on SC increased the electrochemically-active surface area by 1.9 times to 44.5 cm2. This enhanced electron transfer between the electrode and bacteria. Further, embedding carbon nanoparticles into the PPy layer significantly improved biocompatibility as well as changed functional group contents, which were beneficial to bacteria adhesion on electrodes. Taking advantage of high mechanical strength and good conductivity, a large-size PPy/CI/SC was successfully prepared (50 × 60 cm2) demonstrating a promising potential in practical applications. This simple fabrication strategy offers a new idea of developing low cost and scalable electrode materials for high-performance energy harvesting in MFCs.
Microbial fuel cells (MFCs) have various potential applications. However, anode is a main bottleneck that limits electricity production performance of MFCs. Herein, we developed a novel anode based on a stainless steel cloth (SC) modified with carbon nanoparticles of Chinese ink (CI) using polypyrrole (PPy) as a building block (PPy/CI/SC). After modification, PPy/CI/SC showed a 30% shorten in start-up time (36.4 ± 3.3 h vs. 52.3 ± 1.8 h), 33% increase in the maximum current (12.4 ± 1.4 mA vs. 9.3 ± 0.95 mA), and 2.3 times higher in the maximum power density of MFC (61.9 mW/m2 vs. 27.3 mW/m2), compared to Ppy/SC. Experimental results revealed that carbon nanoparticles were able to cover SC uniformly, owing to excellent dispersibility of carbon nanoparticles in CI. The attachment of carbon nanoparticles formed a fluffy layer on SC increased the electrochemically-active surface area by 1.9 times to 44.5 cm2. This enhanced electron transfer between the electrode and bacteria. Further, embedding carbon nanoparticles into the PPy layer significantly improved biocompatibility as well as changed functional group contents, which were beneficial to bacteria adhesion on electrodes. Taking advantage of high mechanical strength and good conductivity, a large-size PPy/CI/SC was successfully prepared (50 × 60 cm2) demonstrating a promising potential in practical applications. This simple fabrication strategy offers a new idea of developing low cost and scalable electrode materials for high-performance energy harvesting in MFCs.
2021, 32(8): 2503-2508
doi: 10.1016/j.cclet.2020.12.043
Abstract:
The textile industry spreads globally with the challenges of its wastewater treatment, especially dyes, which are difficult to degrade. To improve coagulation-flocculation process in dye wastewater treatment, an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride (LiBH4_FeOCl) in this study. The layered crystal pristine iron oxychloride (FeOCl) material was prepared by chemical gas phase migration. LiBH4 was introduced into the layers of two dimensional (2D) FeOCl nanosheets by a simple method of liquid phase insertion. The samples were characterized by a field emitting scanning electron microscopy (SEM), a rotating anode X-ray powder diffractometer (XRD), etc. The cationic dye was employed as the simulated pollutant. A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH4_FeOCl. It is found that the intercalation modified LiBH4_FeOCl exhibits the characteristics of crystal structure, and the layered structure of FeOCl is preserved. LiBH4_FeOCl, as an insoluble inorganic solid coagulant, performs well for dye pollutants of methyl red, basic yellow 1, methylene blue, rhodamine B, ethyl violet and Janus green B. The reaction rate is significantly 68% higher than the current commercial coagulants of Al2(SO4)3. The mechanism analysis reveals that LiBH4_FeOCl breaks and disperses rapidly in the water environment. Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action. The above collaborative actions of breaking, dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH4_FeOCl. The solid inorganic coagulant of LiBH4_FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.
The textile industry spreads globally with the challenges of its wastewater treatment, especially dyes, which are difficult to degrade. To improve coagulation-flocculation process in dye wastewater treatment, an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride (LiBH4_FeOCl) in this study. The layered crystal pristine iron oxychloride (FeOCl) material was prepared by chemical gas phase migration. LiBH4 was introduced into the layers of two dimensional (2D) FeOCl nanosheets by a simple method of liquid phase insertion. The samples were characterized by a field emitting scanning electron microscopy (SEM), a rotating anode X-ray powder diffractometer (XRD), etc. The cationic dye was employed as the simulated pollutant. A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH4_FeOCl. It is found that the intercalation modified LiBH4_FeOCl exhibits the characteristics of crystal structure, and the layered structure of FeOCl is preserved. LiBH4_FeOCl, as an insoluble inorganic solid coagulant, performs well for dye pollutants of methyl red, basic yellow 1, methylene blue, rhodamine B, ethyl violet and Janus green B. The reaction rate is significantly 68% higher than the current commercial coagulants of Al2(SO4)3. The mechanism analysis reveals that LiBH4_FeOCl breaks and disperses rapidly in the water environment. Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action. The above collaborative actions of breaking, dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH4_FeOCl. The solid inorganic coagulant of LiBH4_FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.
2021, 32(8): 2509-2512
doi: 10.1016/j.cclet.2020.12.040
Abstract:
MnOx-CeO2 catalysts are developed by hydrolysis driving redox method using acetate precursor (3Mn1Ce-Ac) and nitrate precursor (3Mn1Ce-N) for the selective catalytic reduction (SCR) of NOx by NH3. A counterpart sample (Cop-3Mn1Ce) was prepared by the NH3·H2O co-precipitation method for comparison purpose. Combining the results of physicochemical properties characterization and performance test, we find that the 3Mn1Ce-Ac catalyst with some nanorod structures is highly active for the deNOx process. The SCR activity of the 3Mn1Ce-Ac catalyst is more admirable than the 3Mn1Ce-N and the Cop-3Mn1Ce catalysts due to plentiful Lewis acid sites, excellent low-temperature reducibility, and superior surface area resulted from O2 generation during the preparation procedure. The 3Mn1Ce-Ac still exhibits the greatest performance for the deNOx process when gaseous acetone is in the SCR feed gas. The NOx conversion and N2 selectivity over the 3Mn1Ce-Ac are both improved by gaseous acetone above 150 ℃ due to the inhibition of SCR undesired side reactions (NSCR & C-O reactions) and "slow-SCR" process.
MnOx-CeO2 catalysts are developed by hydrolysis driving redox method using acetate precursor (3Mn1Ce-Ac) and nitrate precursor (3Mn1Ce-N) for the selective catalytic reduction (SCR) of NOx by NH3. A counterpart sample (Cop-3Mn1Ce) was prepared by the NH3·H2O co-precipitation method for comparison purpose. Combining the results of physicochemical properties characterization and performance test, we find that the 3Mn1Ce-Ac catalyst with some nanorod structures is highly active for the deNOx process. The SCR activity of the 3Mn1Ce-Ac catalyst is more admirable than the 3Mn1Ce-N and the Cop-3Mn1Ce catalysts due to plentiful Lewis acid sites, excellent low-temperature reducibility, and superior surface area resulted from O2 generation during the preparation procedure. The 3Mn1Ce-Ac still exhibits the greatest performance for the deNOx process when gaseous acetone is in the SCR feed gas. The NOx conversion and N2 selectivity over the 3Mn1Ce-Ac are both improved by gaseous acetone above 150 ℃ due to the inhibition of SCR undesired side reactions (NSCR & C-O reactions) and "slow-SCR" process.
2021, 32(8): 2513-2518
doi: 10.1016/j.cclet.2021.01.023
Abstract:
In this study, Mn catalysts have been designed based on manganese oxide octahedral molecular sieve (OMS-2) supports to optimize the catalytic activity in the degradation of organic pollutants. Herein, two different synthetic strategies: Pre-incorporation vs. wet-impregnation have been employed to synthesize [PW]-OMS-2 and [PW]/OMS-2. For [PW]-OMS-2, energy dispersive X-ray spectroscopy (EDX) confirmed that dispersed granular phosphotungstic acid attached and located at the surface of OMS-2, meanwhile some W atoms have been doped into frameworks of OMS-2. However, for [PW]/OMS-2, the W atoms cannot enter the OMS-2 frameworks. A correlation has been established between the different synthetic strategies and catalytic activities. The [PW]-OMS-2 is the most highly effective and stable over than [PW]/OMS-2 and OMS-2 itself for the organic pollutants removal. This may be caused not only by the synergetic effect of [PW] and OMS-2, but also by doping W into frameworks of OMS-2. Therefore, this work provides a new environmentally-friendly and heterogeneous PMS activator and it may be put into practice to degrade organic pollutants.
In this study, Mn catalysts have been designed based on manganese oxide octahedral molecular sieve (OMS-2) supports to optimize the catalytic activity in the degradation of organic pollutants. Herein, two different synthetic strategies: Pre-incorporation vs. wet-impregnation have been employed to synthesize [PW]-OMS-2 and [PW]/OMS-2. For [PW]-OMS-2, energy dispersive X-ray spectroscopy (EDX) confirmed that dispersed granular phosphotungstic acid attached and located at the surface of OMS-2, meanwhile some W atoms have been doped into frameworks of OMS-2. However, for [PW]/OMS-2, the W atoms cannot enter the OMS-2 frameworks. A correlation has been established between the different synthetic strategies and catalytic activities. The [PW]-OMS-2 is the most highly effective and stable over than [PW]/OMS-2 and OMS-2 itself for the organic pollutants removal. This may be caused not only by the synergetic effect of [PW] and OMS-2, but also by doping W into frameworks of OMS-2. Therefore, this work provides a new environmentally-friendly and heterogeneous PMS activator and it may be put into practice to degrade organic pollutants.
2021, 32(8): 2519-2523
doi: 10.1016/j.cclet.2021.02.007
Abstract:
Environmental risks posed by discharge of the emerging contaminant antimony (Sb) into water bodies have raised global concerns recently. The toxicity of Sb has been shown to be species-dependent, with Sb(III) demonstrating much greater toxicity than Sb(V). Here, we proposed an electrochemical filtration system to achieve rapid detoxification of Sb(III) via a non-radical pathway. The key to this technology was an electroactive carbon nanotube filter functionalized with nanoscale Ti-Ce binary oxide. Under an electric field, in situ generated H2O2 could react with the Ti-Ce binary oxide to produce hydroperoxide complexes, which enabled an efficient transformation of Sb(III) to the less toxic Sb(V) (τ < 2 s) at neutral pH. The impact of important operational parameters was assessed and optimized, and system efficacy could be maintained over a wide pH range and long-term operation. An optimum detoxification efficiency of > 90% was achieved using lake water spiked with Sb(III) at 500 μg/L. The results showed that Ti/Ce-hydroperoxo surface complexes were the dominant species responsible for the non-radical oxidation of Sb(III) based on extensive experimental evidences and advanced characterizations. This study provides a robust and effective strategy for the detoxification of water containing Sb(III) and other similar heavy metal ions by integrating state-of-the-art advanced oxidation processes, electrochemistry and nano-filtration technology.
Environmental risks posed by discharge of the emerging contaminant antimony (Sb) into water bodies have raised global concerns recently. The toxicity of Sb has been shown to be species-dependent, with Sb(III) demonstrating much greater toxicity than Sb(V). Here, we proposed an electrochemical filtration system to achieve rapid detoxification of Sb(III) via a non-radical pathway. The key to this technology was an electroactive carbon nanotube filter functionalized with nanoscale Ti-Ce binary oxide. Under an electric field, in situ generated H2O2 could react with the Ti-Ce binary oxide to produce hydroperoxide complexes, which enabled an efficient transformation of Sb(III) to the less toxic Sb(V) (τ < 2 s) at neutral pH. The impact of important operational parameters was assessed and optimized, and system efficacy could be maintained over a wide pH range and long-term operation. An optimum detoxification efficiency of > 90% was achieved using lake water spiked with Sb(III) at 500 μg/L. The results showed that Ti/Ce-hydroperoxo surface complexes were the dominant species responsible for the non-radical oxidation of Sb(III) based on extensive experimental evidences and advanced characterizations. This study provides a robust and effective strategy for the detoxification of water containing Sb(III) and other similar heavy metal ions by integrating state-of-the-art advanced oxidation processes, electrochemistry and nano-filtration technology.
2021, 32(8): 2524-2528
doi: 10.1016/j.cclet.2021.01.044
Abstract:
To enhance the photodegradation ability of CeO2 for organic dyes, an effective strategy is to introduce oxygen vacancies (Vo). In general, the introduced Vo are simultaneously present both on the surface and in the bulk of CeO2. The surface oxygen vacancies (Vo-s) can decrease the band gap, thus enhancing light absorption to produce more photogenerated e− for photodegradation. However, the bulk oxygen vacancies (Vo-b) will inhibit photocatalytic activity by increasing the recombination of photogenerated e− and Vo-b. Therefore, regulating the concentrations of Vo-s to Vo-b is a breakthrough for achieving the best utilization of photogenerated e− during photodegradation. We used an easy hydrothermal method to achieve tunable concentrations of Vo-s to Vo-b in CeO2 nanorods. The optimized CeO2 presents a 70.2% removal of rhodamine B after 120 min of ultraviolet−visible light irradiation, and a superior photodegradation performance of multiple organics. This tuning strategy for Vo also provides guidance for developing other advanced metal-oxide semiconductor photocatalysts for the photodegradation of organic dyes.
To enhance the photodegradation ability of CeO2 for organic dyes, an effective strategy is to introduce oxygen vacancies (Vo). In general, the introduced Vo are simultaneously present both on the surface and in the bulk of CeO2. The surface oxygen vacancies (Vo-s) can decrease the band gap, thus enhancing light absorption to produce more photogenerated e− for photodegradation. However, the bulk oxygen vacancies (Vo-b) will inhibit photocatalytic activity by increasing the recombination of photogenerated e− and Vo-b. Therefore, regulating the concentrations of Vo-s to Vo-b is a breakthrough for achieving the best utilization of photogenerated e− during photodegradation. We used an easy hydrothermal method to achieve tunable concentrations of Vo-s to Vo-b in CeO2 nanorods. The optimized CeO2 presents a 70.2% removal of rhodamine B after 120 min of ultraviolet−visible light irradiation, and a superior photodegradation performance of multiple organics. This tuning strategy for Vo also provides guidance for developing other advanced metal-oxide semiconductor photocatalysts for the photodegradation of organic dyes.
2021, 32(8): 2529-2533
doi: 10.1016/j.cclet.2021.01.031
Abstract:
Bimetallic nanoparticles modified hollow-structured nanoporous carbons (NPCs) have been fabricated via a convenient one-step carbonizing strategy derived from covalent organic framework. The Pd/Fe/NPCs, Pt/Fe/NPCs and Rh/Fe/NPCs were obtained and can be used as Fenton-like catalysts with good stability and reusability. The catalytic activity was evaluated by the degradation of 2, 4-dichlorophenl (2, 4-DCP). These fabricated bimetallic catalysts exhibited much higher catalytic activity than Fe/NPCs at room temperature. The enhancement of catalytic ability was benefited from synergetic catalytic effect of bimetallic nanoparticles and accelerated mass transfer of hollow structure. Additionally, the enhanced catalytic mechanism of bimetallic catalysts was studied in detail and the reasonable reaction pathway was proposed. Besides, the bimetallic catalysts were successfully used for degradation of 2, 4-DCP in actual industrial wastewater and the removal efficiency could reach 74.3% within 120 min, which demonstrated the promising potential application of bimetallic catalysts in the removal of pollutants in environment.
Bimetallic nanoparticles modified hollow-structured nanoporous carbons (NPCs) have been fabricated via a convenient one-step carbonizing strategy derived from covalent organic framework. The Pd/Fe/NPCs, Pt/Fe/NPCs and Rh/Fe/NPCs were obtained and can be used as Fenton-like catalysts with good stability and reusability. The catalytic activity was evaluated by the degradation of 2, 4-dichlorophenl (2, 4-DCP). These fabricated bimetallic catalysts exhibited much higher catalytic activity than Fe/NPCs at room temperature. The enhancement of catalytic ability was benefited from synergetic catalytic effect of bimetallic nanoparticles and accelerated mass transfer of hollow structure. Additionally, the enhanced catalytic mechanism of bimetallic catalysts was studied in detail and the reasonable reaction pathway was proposed. Besides, the bimetallic catalysts were successfully used for degradation of 2, 4-DCP in actual industrial wastewater and the removal efficiency could reach 74.3% within 120 min, which demonstrated the promising potential application of bimetallic catalysts in the removal of pollutants in environment.
2021, 32(8): 2534-2538
doi: 10.1016/j.cclet.2020.12.049
Abstract:
Semiconductor-mediated photocatalysis is a promising photochemical process for harvesting inexhaustible solar energy to address the energy crisis and environmental issues. However, the low solar-light response and poor carrier migration are severe drawbacks that limit its practical application. Herein, we propose a convenient pathway for improving electron-hole separation and solar energy utilisation by engineering defective ZnIn2S4 with doping of carbon dots. The optimum ZnIn2S4/CD200 nanosheet exhibited 100% diclofenac (DCF) degradation within 12 min under visible-light. The estimated photocatalytic efficiency under natural sunlight was 98.2%. Scavenging experiments and electron spin resonance (ESR) analysis indicated that the superoxide radical (O2∙−), photoelectron (e−), hole (h+) and hydroxyl radical (∙OH) were the predominant contributions in the ZnIn2S4/CD200/DCF/visible light system. Furthermore, ZnIn2S4/CD200 exhibited excellent reusability and stability after 4 times recycling. The photodegradation routes mainly involved hydroxylation, decarboxylation, CN bond cleavage, dechlorination, ring closure, and ring-opening. The ecological risk assessment and total organic carbon (TOC) tests exhibited desirable toxicity reduction and mineralization results. These observations not only offer a facile strategy for the construction of defective ZnIn2S4, but also pioneer the direct utilisation of natural light for highly efficient environmental remediation.
Semiconductor-mediated photocatalysis is a promising photochemical process for harvesting inexhaustible solar energy to address the energy crisis and environmental issues. However, the low solar-light response and poor carrier migration are severe drawbacks that limit its practical application. Herein, we propose a convenient pathway for improving electron-hole separation and solar energy utilisation by engineering defective ZnIn2S4 with doping of carbon dots. The optimum ZnIn2S4/CD200 nanosheet exhibited 100% diclofenac (DCF) degradation within 12 min under visible-light. The estimated photocatalytic efficiency under natural sunlight was 98.2%. Scavenging experiments and electron spin resonance (ESR) analysis indicated that the superoxide radical (O2∙−), photoelectron (e−), hole (h+) and hydroxyl radical (∙OH) were the predominant contributions in the ZnIn2S4/CD200/DCF/visible light system. Furthermore, ZnIn2S4/CD200 exhibited excellent reusability and stability after 4 times recycling. The photodegradation routes mainly involved hydroxylation, decarboxylation, CN bond cleavage, dechlorination, ring closure, and ring-opening. The ecological risk assessment and total organic carbon (TOC) tests exhibited desirable toxicity reduction and mineralization results. These observations not only offer a facile strategy for the construction of defective ZnIn2S4, but also pioneer the direct utilisation of natural light for highly efficient environmental remediation.
2021, 32(8): 2539-2543
doi: 10.1016/j.cclet.2020.12.016
Abstract:
Constructing a heterojunction photocatalyst is a significant method to enhance photocatalytic activity because it can promote the separation of photogenerated carriers. Herein, amorphous/crystalline contact Bi2S3/Bi4O7 heterostructure was successfully synthesized by in-situ sulfidation of Bi4O7. The amorphous Bi2S3 is diffused on the surface of Bi4O7 rod, enhancing the visible light response and improving the transport of photogenerated carriers. Various characterizations confirm that the rapid separation of photogenerated carriers leads to increased photocatalytic performance. The optimized Bi2S3/Bi4O7 heterostructure photocatalyst (BiS-0.15) exhibits the highest Cr(VI) reduction (0.01350 min−1) and RhB oxidation (0.08011 min−1) activity, which is much higher than that of pure Bi4O7 and Bi2S3/Bi4O7 mixture under visible light irradiation. This work provides new insights into the construction of efficient novel photocatalysts.
Constructing a heterojunction photocatalyst is a significant method to enhance photocatalytic activity because it can promote the separation of photogenerated carriers. Herein, amorphous/crystalline contact Bi2S3/Bi4O7 heterostructure was successfully synthesized by in-situ sulfidation of Bi4O7. The amorphous Bi2S3 is diffused on the surface of Bi4O7 rod, enhancing the visible light response and improving the transport of photogenerated carriers. Various characterizations confirm that the rapid separation of photogenerated carriers leads to increased photocatalytic performance. The optimized Bi2S3/Bi4O7 heterostructure photocatalyst (BiS-0.15) exhibits the highest Cr(VI) reduction (0.01350 min−1) and RhB oxidation (0.08011 min−1) activity, which is much higher than that of pure Bi4O7 and Bi2S3/Bi4O7 mixture under visible light irradiation. This work provides new insights into the construction of efficient novel photocatalysts.
2021, 32(8): 2572-2576
doi: 10.1016/j.cclet.2021.03.071
Abstract:
In this paper, the host-guest interaction of cucurbit[7]uril (Q[7]) and chromone (CMO) has been developed as a fluorescent probe for the highly selective detection of Zn2+ and Cd2+ in water based on a chelation-enhanced fluorescence (CHEF) mechanism. There was a good linear relationship between the fluorescence intensity of the CMO@Q[7] probe and the concentration of Zn2+ or Cd2+ in the range of 0–3.0 × 10–5 mol/L and the detection limit for Zn2+ and Cd2+ was found to be 2.03 × 10–6 mol/L and 1.89 × 10–6 mol/L, respectively. The X-ray crystal structure indicated that different coordination fashions were triggered by Zn2+ and Cd2+ in the CMO@Q[7] complexes, respectively. However, both metal ions coordinated with the carbonyl oxygen of CMO, which was encapsulated in the cavity of Q[7], thus leading to the enhancement of recognition fluorescence emission of CMO.
In this paper, the host-guest interaction of cucurbit[7]uril (Q[7]) and chromone (CMO) has been developed as a fluorescent probe for the highly selective detection of Zn2+ and Cd2+ in water based on a chelation-enhanced fluorescence (CHEF) mechanism. There was a good linear relationship between the fluorescence intensity of the CMO@Q[7] probe and the concentration of Zn2+ or Cd2+ in the range of 0–3.0 × 10–5 mol/L and the detection limit for Zn2+ and Cd2+ was found to be 2.03 × 10–6 mol/L and 1.89 × 10–6 mol/L, respectively. The X-ray crystal structure indicated that different coordination fashions were triggered by Zn2+ and Cd2+ in the CMO@Q[7] complexes, respectively. However, both metal ions coordinated with the carbonyl oxygen of CMO, which was encapsulated in the cavity of Q[7], thus leading to the enhancement of recognition fluorescence emission of CMO.
2021, 32(8): 2577-2581
doi: 10.1016/j.cclet.2021.03.010
Abstract:
A visible light and base promoted O-H insertion/cyclization of para-quinone methides with aryl diazoacetates is developed. This one-pot two step reaction offers a mild and efficient approach for the synthesis of biologically important 2, 3-dihydrobenzofuran derivatives in good yields and moderate diastereoselectivities.
A visible light and base promoted O-H insertion/cyclization of para-quinone methides with aryl diazoacetates is developed. This one-pot two step reaction offers a mild and efficient approach for the synthesis of biologically important 2, 3-dihydrobenzofuran derivatives in good yields and moderate diastereoselectivities.
2021, 32(8): 2582-2586
doi: 10.1016/j.cclet.2021.02.047
Abstract:
Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.
Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.
2021, 32(8): 2587-2591
doi: 10.1016/j.cclet.2021.02.050
Abstract:
An intramolecular selenocyclizations of olefins mediated by a commercially available hypervalent iodine(III) reagent, PhIO, was developed. This method provided access to a wide range of selenenylated heterocycles under ambient conditions. The striking advantages of this protocol over all previous methods include mild reaction conditions, easy operation, good yields, high levels of functional group compatibility, large–scale application and suitability for the late-stage functionalization of complex molecules of biological importance.
An intramolecular selenocyclizations of olefins mediated by a commercially available hypervalent iodine(III) reagent, PhIO, was developed. This method provided access to a wide range of selenenylated heterocycles under ambient conditions. The striking advantages of this protocol over all previous methods include mild reaction conditions, easy operation, good yields, high levels of functional group compatibility, large–scale application and suitability for the late-stage functionalization of complex molecules of biological importance.
2021, 32(8): 2592-2596
doi: 10.1016/j.cclet.2021.02.061
Abstract:
A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(III)-catalyzed [4 + 2] annulation of N-arylbenzamidines with 1, 4, 2-dioxazol-5-ones. This reaction features excellent regioselectivity, broad substrate scope and high step economy, which would provide the reference for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds.
A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(III)-catalyzed [4 + 2] annulation of N-arylbenzamidines with 1, 4, 2-dioxazol-5-ones. This reaction features excellent regioselectivity, broad substrate scope and high step economy, which would provide the reference for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds.
