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2021 Volume 21 Issue 7
2021, 32(7): 2097-2107
doi: 10.1016/j.cclet.2020.11.070
Abstract:
As a close relative of ferroelectricity, antiferroelectricity has received a recent resurgence of interest driven by technological aspirations in energy-efficient applications, such as energy storage capacitors, solid-state cooling devices, explosive energy conversion, and displacement transducers. Though prolonged efforts in this area have led to certain progress and the discovery of more than 100 antiferroelectric materials over the last 70 years, some scientific and technological issues remain unresolved. Herein, we provide perspectives on the development of antiferroelectrics for energy storage and conversion applications, as well as a comprehensive understanding of the structural origin of antiferroelectricity and field-induced phase transitions, followed by design strategies for new lead-free antiferroelectrics. We also envision unprecedented challenges in the development of promising antiferroelectric materials that bridge materials design and real applications. Future research in these directions will open up new possibilities in resolving the mystery of antiferroelectricity, provide opportunities for comprehending structure-property correlation and developing antiferroelectric/ferroelectric theories, and suggest an approach to the manipulation of phase transitions for real-world applications.
As a close relative of ferroelectricity, antiferroelectricity has received a recent resurgence of interest driven by technological aspirations in energy-efficient applications, such as energy storage capacitors, solid-state cooling devices, explosive energy conversion, and displacement transducers. Though prolonged efforts in this area have led to certain progress and the discovery of more than 100 antiferroelectric materials over the last 70 years, some scientific and technological issues remain unresolved. Herein, we provide perspectives on the development of antiferroelectrics for energy storage and conversion applications, as well as a comprehensive understanding of the structural origin of antiferroelectricity and field-induced phase transitions, followed by design strategies for new lead-free antiferroelectrics. We also envision unprecedented challenges in the development of promising antiferroelectric materials that bridge materials design and real applications. Future research in these directions will open up new possibilities in resolving the mystery of antiferroelectricity, provide opportunities for comprehending structure-property correlation and developing antiferroelectric/ferroelectric theories, and suggest an approach to the manipulation of phase transitions for real-world applications.
2021, 32(7): 2108-2116
doi: 10.1016/j.cclet.2020.11.051
Abstract:
Water electrolysis technology holds the perfect promise of the hydrogen production, yet control of efficiency and rate of water electrolysis greatly relies on the availability of high-performance electrode materials for kinetic-sluggish oxygen evolution reaction (OER). Accordingly, substantial endeavors have been made to explore advanced electrode materials over the past decade. Recently, RuO2 and RuO2-based materials have been demonstrated to be promising for OER due to their remarkable electrocatalytic activity and pH-universal application. Herein, the great achievements and progresses of this flourishing spot are comprehensively reviewed, which are started by a general description of OER to understand the reaction mechanism in detail. Subsequently, the key advantages and issues of RuO2 towards OER are also introduced, followed by proposing many advanced strategies for further promoting the electrocatalytic OER performance of RuO2. Finally, the daunting challenges and future progresses of RuO2 electrocatalysts toward practical water oxidation are highlighted, aiming to provide guidance for the fabrication of desirable RuO2-based electrocatalysts toward OER.
Water electrolysis technology holds the perfect promise of the hydrogen production, yet control of efficiency and rate of water electrolysis greatly relies on the availability of high-performance electrode materials for kinetic-sluggish oxygen evolution reaction (OER). Accordingly, substantial endeavors have been made to explore advanced electrode materials over the past decade. Recently, RuO2 and RuO2-based materials have been demonstrated to be promising for OER due to their remarkable electrocatalytic activity and pH-universal application. Herein, the great achievements and progresses of this flourishing spot are comprehensively reviewed, which are started by a general description of OER to understand the reaction mechanism in detail. Subsequently, the key advantages and issues of RuO2 towards OER are also introduced, followed by proposing many advanced strategies for further promoting the electrocatalytic OER performance of RuO2. Finally, the daunting challenges and future progresses of RuO2 electrocatalysts toward practical water oxidation are highlighted, aiming to provide guidance for the fabrication of desirable RuO2-based electrocatalysts toward OER.
2021, 32(7): 2117-2126
doi: 10.1016/j.cclet.2021.01.048
Abstract:
Owing to the special formation of photopolymerized hydrogels, they can effectively control the formation of hydrogels in space and time. Moreover, the photopolymerized hydrogels have mild formation conditions and biocompatibility; therefore, they can be widely used in tissue engineering. With the development and application of manufacturing technology, photopolymerized hydrogels can be widely used in cell encapsulation, scaffold materials, and other tissue engineering fields through more elaborate manufacturing methods. This review covers the types of photoinitiators, manufacturing technologies for photopolymerized hydrogels as well as the materials used, and a summary of the applications of photopolymerized hydrogels in tissue engineering.
Owing to the special formation of photopolymerized hydrogels, they can effectively control the formation of hydrogels in space and time. Moreover, the photopolymerized hydrogels have mild formation conditions and biocompatibility; therefore, they can be widely used in tissue engineering. With the development and application of manufacturing technology, photopolymerized hydrogels can be widely used in cell encapsulation, scaffold materials, and other tissue engineering fields through more elaborate manufacturing methods. This review covers the types of photoinitiators, manufacturing technologies for photopolymerized hydrogels as well as the materials used, and a summary of the applications of photopolymerized hydrogels in tissue engineering.
2021, 32(7): 2127-2138
doi: 10.1016/j.cclet.2021.02.015
Abstract:
Chemodynamic therapy (CDT) is an emerging endogenous stimulation activated tumor treatment approach that exploiting iron-containing nanomedicine as catalyst to convert hydrogen peroxide (H2O2) into toxic hydroxyl radical (·OH) through Fenton reaction. Due to the unique characteristics (weak acidity and the high H2O2 level) of the tumor microenvironment, CDT has advantages of high selectivity and low side effect. However, as an important substrate of Fenton reaction, the endogenous H2O2 in tumor is still insufficient, which may be an important factor limiting the efficacy of CDT. In order to optimize CDT, various H2O2-generating nanomedicines that can promote the production of H2O2 in tumor have been designed and developed for enhanced CDT. In this review, we summarize recently developed nanomedicines based on catalytic enzymes, nanozymes, drugs, metal peroxides and bacteria. Finally, the challenges and possible development directions for further enhancing CDT are prospected.
Chemodynamic therapy (CDT) is an emerging endogenous stimulation activated tumor treatment approach that exploiting iron-containing nanomedicine as catalyst to convert hydrogen peroxide (H2O2) into toxic hydroxyl radical (·OH) through Fenton reaction. Due to the unique characteristics (weak acidity and the high H2O2 level) of the tumor microenvironment, CDT has advantages of high selectivity and low side effect. However, as an important substrate of Fenton reaction, the endogenous H2O2 in tumor is still insufficient, which may be an important factor limiting the efficacy of CDT. In order to optimize CDT, various H2O2-generating nanomedicines that can promote the production of H2O2 in tumor have been designed and developed for enhanced CDT. In this review, we summarize recently developed nanomedicines based on catalytic enzymes, nanozymes, drugs, metal peroxides and bacteria. Finally, the challenges and possible development directions for further enhancing CDT are prospected.
2021, 32(7): 2139-2142
doi: 10.1016/j.cclet.2020.11.022
Abstract:
In this work, the phase-transitioned BSA (PTB) film using the mild and fast fabrication process adhered to the capillary inner wall uniformly, and the fabricated PTB film-coated capillary column was applied to realize open tubular capillary electrochromatography (OT-CEC) enantioseparation. The enantioseparation ability of PTB film-coated capillary was evaluated with eight pairs of chiral analytes including drugs and neurotransmitters, all achieving good resolution and symmetrical peak shape. For three consecutive runs, the relative standard deviations (RSD) of migration time for intra-day, inter-day, and column-to-column repeatability were in the range of 0.3%–3.5%, 0.2%–4.9% and 2.1%–7.7%, respectively. Moreover, the PTB film-coated capillary column ran continuously over 300 times with high separation efficiency. Therefore, the coating method based on BSA self-assembly supramolecular film can be extended to the preparation of other proteinaceous capillary columns.
In this work, the phase-transitioned BSA (PTB) film using the mild and fast fabrication process adhered to the capillary inner wall uniformly, and the fabricated PTB film-coated capillary column was applied to realize open tubular capillary electrochromatography (OT-CEC) enantioseparation. The enantioseparation ability of PTB film-coated capillary was evaluated with eight pairs of chiral analytes including drugs and neurotransmitters, all achieving good resolution and symmetrical peak shape. For three consecutive runs, the relative standard deviations (RSD) of migration time for intra-day, inter-day, and column-to-column repeatability were in the range of 0.3%–3.5%, 0.2%–4.9% and 2.1%–7.7%, respectively. Moreover, the PTB film-coated capillary column ran continuously over 300 times with high separation efficiency. Therefore, the coating method based on BSA self-assembly supramolecular film can be extended to the preparation of other proteinaceous capillary columns.
2021, 32(7): 2143-2150
doi: 10.1016/j.cclet.2020.11.017
Abstract:
Being abundant and active, Fe2O3 is suitable for selective oxidation of H2S. However, its practical application is limited due to the poor sulfur selectivity and rapid deactivation. Herein, we report a facile template-free hydrothermal method to fabricate porous α-Fe2O3/SnO2 composites with hierarchical nanoflower that can obviously improve the catalytic performance of Fe2O3. It was disclosed that the synergistic effect between α-Fe2O3 and SnO2 promotes the physico-chemical properties of α-Fe2O3/SnO2 composites. Specifically, the electron transfer between the Fe2+/Fe3+ and Sn2+/Sn4+ redox couples enhances the reducibility of α-Fe2O3/SnO2 composites. The number of oxygen vacancies is improved when the Fe cations incorporate into SnO2 structure, which facilitates the adsorption and activation of oxygen species. Additionally, the porous structure improves the accessibility of H2S to active sites. Among the composites, Fe1Sn1 exhibits complete H2S conversion with 100% sulfur selectivity at 220 ℃, better than those of pure α-Fe2O3 and SnO2. Moreover, Fe1Sn1 catalyst shows high stability and water resistance.
Being abundant and active, Fe2O3 is suitable for selective oxidation of H2S. However, its practical application is limited due to the poor sulfur selectivity and rapid deactivation. Herein, we report a facile template-free hydrothermal method to fabricate porous α-Fe2O3/SnO2 composites with hierarchical nanoflower that can obviously improve the catalytic performance of Fe2O3. It was disclosed that the synergistic effect between α-Fe2O3 and SnO2 promotes the physico-chemical properties of α-Fe2O3/SnO2 composites. Specifically, the electron transfer between the Fe2+/Fe3+ and Sn2+/Sn4+ redox couples enhances the reducibility of α-Fe2O3/SnO2 composites. The number of oxygen vacancies is improved when the Fe cations incorporate into SnO2 structure, which facilitates the adsorption and activation of oxygen species. Additionally, the porous structure improves the accessibility of H2S to active sites. Among the composites, Fe1Sn1 exhibits complete H2S conversion with 100% sulfur selectivity at 220 ℃, better than those of pure α-Fe2O3 and SnO2. Moreover, Fe1Sn1 catalyst shows high stability and water resistance.
2021, 32(7): 2151-2154
doi: 10.1016/j.cclet.2020.11.054
Abstract:
Carbon nanotube film (CNTF) can be used for photocatalysis and water treatment due to its porous structure, good stability and excellent electrical properties. In this work, TiO2/amorphous carbon/carbon nanotube film (TCC) composite with uniform structure was prepared by a simple atomization spraying method. Rhodamine B (RhB) was used to test the photocatalytic activity of TCC. TCC composite exhibits good photocatalytic activity under ultraviolet light. In particular, the degradation efficiency of rhodamine B (RhB) by TCC sprayed with 9 layers of TiO2 (9TCC) increased by 1.45 times than of TiO2 under ultraviolet light. The enhanced photocatalytic activity of TCC is attributed to the CNTF, which can broaden the light response range of TCC and improve the migration efficiency of electrons. The existence of amorphous carbon will promote these advances. Moreover, the better hydrophilic properties would enhance the catalytic performance happened on the solid-liquid interface. Finally, the photocatalytic mechanism and degradation intermediates of the TCC composite were proposed.
Carbon nanotube film (CNTF) can be used for photocatalysis and water treatment due to its porous structure, good stability and excellent electrical properties. In this work, TiO2/amorphous carbon/carbon nanotube film (TCC) composite with uniform structure was prepared by a simple atomization spraying method. Rhodamine B (RhB) was used to test the photocatalytic activity of TCC. TCC composite exhibits good photocatalytic activity under ultraviolet light. In particular, the degradation efficiency of rhodamine B (RhB) by TCC sprayed with 9 layers of TiO2 (9TCC) increased by 1.45 times than of TiO2 under ultraviolet light. The enhanced photocatalytic activity of TCC is attributed to the CNTF, which can broaden the light response range of TCC and improve the migration efficiency of electrons. The existence of amorphous carbon will promote these advances. Moreover, the better hydrophilic properties would enhance the catalytic performance happened on the solid-liquid interface. Finally, the photocatalytic mechanism and degradation intermediates of the TCC composite were proposed.
2021, 32(7): 2155-2158
doi: 10.1016/j.cclet.2020.11.069
Abstract:
A heterojunction of Sm-doped g-C3N4/Ti3C2 MXene (SCN/MX) was constructed via prepolymerization and solid mixture-calcination method. The modified g-C3N4 presented a hollow porous seaweed-like shape which can increase its specific area and active sites. In SCN/MX composite, the optical properties, no matter optical absorption ability or separation performance of photo-induced electrons and holes, were enhanced. Among them, Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination, and Ti3C2 MXene would broaden light absorption and further improve the carrier migration efficiency. The SCN/MX presented higher photocatalytic degradation efficiency (> 99%) of ciprofloxacin under visible light irradiation. The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes. The degradation mechanisms of ciprofloxacin (CIP) over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring, and the final products were CO2, H2O and F−.
A heterojunction of Sm-doped g-C3N4/Ti3C2 MXene (SCN/MX) was constructed via prepolymerization and solid mixture-calcination method. The modified g-C3N4 presented a hollow porous seaweed-like shape which can increase its specific area and active sites. In SCN/MX composite, the optical properties, no matter optical absorption ability or separation performance of photo-induced electrons and holes, were enhanced. Among them, Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination, and Ti3C2 MXene would broaden light absorption and further improve the carrier migration efficiency. The SCN/MX presented higher photocatalytic degradation efficiency (> 99%) of ciprofloxacin under visible light irradiation. The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes. The degradation mechanisms of ciprofloxacin (CIP) over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring, and the final products were CO2, H2O and F−.
2021, 32(7): 2159-2163
doi: 10.1016/j.cclet.2020.12.001
Abstract:
Injectable hydrogels have been considered as promising materials for bone regeneration, but their osteoinduction and mechanical performance are yet to be improved. In this study, a novel biocompatible injectable and self-healing nano hybrid hydrogel was on-demand prepared via a fast (within 30 s) and easy gelation approach by reversible Schiff base formed between −CH=O of oxidized sodium alginate (OSA) and −NH2 of glycol chitosan (GCS) mixed with calcium phosphate nanoparticles (CaP NPs). Its raw materials can be ready in large quantities by a simple synthesis process. The mechanical strength, degradation and swelling behavior of the hydrogel can be readily controlled by simply controlling the molar ratio of −CH=O and −NH2. This hydrogel exhibits pH responsiveness, good degradability and biocompatibility. The hydrogel used as the matrix for mesenchymal stem cells can significantly induce the proliferation, differentiation and osteoinduction in vitro. These results showed this novel hydrogel is an ideal candidate for applications in bone tissue regeneration and drug delivery.
Injectable hydrogels have been considered as promising materials for bone regeneration, but their osteoinduction and mechanical performance are yet to be improved. In this study, a novel biocompatible injectable and self-healing nano hybrid hydrogel was on-demand prepared via a fast (within 30 s) and easy gelation approach by reversible Schiff base formed between −CH=O of oxidized sodium alginate (OSA) and −NH2 of glycol chitosan (GCS) mixed with calcium phosphate nanoparticles (CaP NPs). Its raw materials can be ready in large quantities by a simple synthesis process. The mechanical strength, degradation and swelling behavior of the hydrogel can be readily controlled by simply controlling the molar ratio of −CH=O and −NH2. This hydrogel exhibits pH responsiveness, good degradability and biocompatibility. The hydrogel used as the matrix for mesenchymal stem cells can significantly induce the proliferation, differentiation and osteoinduction in vitro. These results showed this novel hydrogel is an ideal candidate for applications in bone tissue regeneration and drug delivery.
2021, 32(7): 2164-2168
doi: 10.1016/j.cclet.2020.11.064
Abstract:
Inflammation is a defense mechanism associated with a wide range of diseases. Celastrol is a small molecule isolated from traditional Chinese medicine with potent anti-inflammation activity. In this study, we established an integrated quantitative proteomics strategy to investigate the acute response to celastrol treatment in a rat macrophage cell line challenged with lipopolysaccharide (LPS). Both stable-isotopic based non-targeted quantitative profiling and PRM-based targeted quantitation methods were employed. Dimethyl-labeling based non-targeted profiling revealed 28 and 52 proteins that significantly up- and down-regulated by celastrol. Bioinformatics analysis pinpoint key signaling pathways affected. Seven proteins were selected for examining their time-dependent regulatory pattern in response to celastrol using targeted PRM quantitation. The abundance of mRNA at multiple time-points of selected proteins was also examined. Celastrol induced an acute response of selected key transcriptional factors in terms of mRNA or protein abundance within one hour. Interestingly, regulatory trend of mRNA and protein abundance suggested a novel dual mechanism of celastrol in the terms of acute anti-inflammation. The integrated quantitative proteomic strategy established in this study constitutes an efficient workflow to characterize key components and their time-dependent regulatory pattern for monitoring drug response.
Inflammation is a defense mechanism associated with a wide range of diseases. Celastrol is a small molecule isolated from traditional Chinese medicine with potent anti-inflammation activity. In this study, we established an integrated quantitative proteomics strategy to investigate the acute response to celastrol treatment in a rat macrophage cell line challenged with lipopolysaccharide (LPS). Both stable-isotopic based non-targeted quantitative profiling and PRM-based targeted quantitation methods were employed. Dimethyl-labeling based non-targeted profiling revealed 28 and 52 proteins that significantly up- and down-regulated by celastrol. Bioinformatics analysis pinpoint key signaling pathways affected. Seven proteins were selected for examining their time-dependent regulatory pattern in response to celastrol using targeted PRM quantitation. The abundance of mRNA at multiple time-points of selected proteins was also examined. Celastrol induced an acute response of selected key transcriptional factors in terms of mRNA or protein abundance within one hour. Interestingly, regulatory trend of mRNA and protein abundance suggested a novel dual mechanism of celastrol in the terms of acute anti-inflammation. The integrated quantitative proteomic strategy established in this study constitutes an efficient workflow to characterize key components and their time-dependent regulatory pattern for monitoring drug response.
2021, 32(7): 2169-2173
doi: 10.1016/j.cclet.2020.12.018
Abstract:
Fe-based compounds with good environmental friendliness and high reversible capacity have attracted considerable attention as anode for lithium-ion batteries. But, similar to other transition metal oxides (TMOs), it is also affected by large volume changes and inferior kinetics during redox reactions, resulting in the destruction of the crystal structure and poor electrochemical performance. Here, Fe3O4/C nanospheres anchored on the two-dimensional graphene oxide as precursors are phosphated and sintered to build the multiphasic nanocomposite. XRD results confirmed the multiphasic nanocomposite composed of Fe2O3, Fe3O4 and Fe3PO7, which will facilitate the Li+ diffusion. And the carbonaceous matrix will buffer the volume changes and enhance electron conduction. Consequently, the multiphasic Fe-based anode delivers a large specific capacity of 1086 mAh/g with a high initial Coulombic efficiency of 87% at 0.1 C. It also has excellent cycling stability and rate property, maintaining a capacity retention of ~87% after 300 cycles and a high reversible capacity of 632 mAh/g at 10 C. The proposed multiphasic structure offers a new insight into improving the electrochemical properties of TMO-based anodes for advanced alkali-ion batteries.
Fe-based compounds with good environmental friendliness and high reversible capacity have attracted considerable attention as anode for lithium-ion batteries. But, similar to other transition metal oxides (TMOs), it is also affected by large volume changes and inferior kinetics during redox reactions, resulting in the destruction of the crystal structure and poor electrochemical performance. Here, Fe3O4/C nanospheres anchored on the two-dimensional graphene oxide as precursors are phosphated and sintered to build the multiphasic nanocomposite. XRD results confirmed the multiphasic nanocomposite composed of Fe2O3, Fe3O4 and Fe3PO7, which will facilitate the Li+ diffusion. And the carbonaceous matrix will buffer the volume changes and enhance electron conduction. Consequently, the multiphasic Fe-based anode delivers a large specific capacity of 1086 mAh/g with a high initial Coulombic efficiency of 87% at 0.1 C. It also has excellent cycling stability and rate property, maintaining a capacity retention of ~87% after 300 cycles and a high reversible capacity of 632 mAh/g at 10 C. The proposed multiphasic structure offers a new insight into improving the electrochemical properties of TMO-based anodes for advanced alkali-ion batteries.
2021, 32(7): 2174-2178
doi: 10.1016/j.cclet.2020.11.060
Abstract:
Chinese herbal medicines (CHMs) play an increasingly important role in the field of medicine and affects public health in the world. Although more and more strict has been employed to ensure the quality and safety of CHMs, pesticide residues in CHMs remain a serious issue and are the bottleneck for the global development of CHMs. In this work, we applied molecularly imprinted membrane electrospray mass spectrometry (MIM-ESI MS) for rapid detecting 4 classes of pesticide residues in CHMs, including organophosphorus (OPP), carbamates, pyrethroids and neonicotinoids in CHMs. Compared with our previous ambient ionization method MESI, MIM-ESI is capable of achieving a ~50-fold increase in the detection limit of conventional analytical methods owing to the specificity recognition and unique enrichment of MIM. The optimal experimental conditions were determined, and the method was further validated for its sensitivity and specificity. Our data showed that MIM-ESI MS is applicable for the direct quantitation of pesticide residues in CHMs. This detection technology may help to ensure the quality of CHMs in the future.
Chinese herbal medicines (CHMs) play an increasingly important role in the field of medicine and affects public health in the world. Although more and more strict has been employed to ensure the quality and safety of CHMs, pesticide residues in CHMs remain a serious issue and are the bottleneck for the global development of CHMs. In this work, we applied molecularly imprinted membrane electrospray mass spectrometry (MIM-ESI MS) for rapid detecting 4 classes of pesticide residues in CHMs, including organophosphorus (OPP), carbamates, pyrethroids and neonicotinoids in CHMs. Compared with our previous ambient ionization method MESI, MIM-ESI is capable of achieving a ~50-fold increase in the detection limit of conventional analytical methods owing to the specificity recognition and unique enrichment of MIM. The optimal experimental conditions were determined, and the method was further validated for its sensitivity and specificity. Our data showed that MIM-ESI MS is applicable for the direct quantitation of pesticide residues in CHMs. This detection technology may help to ensure the quality of CHMs in the future.
2021, 32(7): 2179-2182
doi: 10.1016/j.cclet.2020.12.002
Abstract:
Developing an excellent photocatalysis system to remove pesticides from water is an urgent problem in current environment purification field. Herein, a Z-scheme WO3/g-C3N4 photocatalyst was prepared by a facile in-situ calcination method, and the photocatalytic activity was investigated for degradation of nitenpyram (NTP) under visible light. The optimal Z-scheme WO3/g-C3N4 photocatalyst displayed the highest rate constant (0.036 min−1), which is about 1.7 and 25 times higher than that of pure g-C3N4 and WO3, respectively. The improvement of photocatalytic performance is attributed to fast transfer of photogenerated carriers in the Z-scheme structure, which are testified by electron spin resonance (ESR) experiments, photocurrent and electrochemical impedance spectra (EIS) measurements. Moreover, the effects of typical water environmental factors on the degradation NTP were systematically studied. And the possible degradation pathways of NTP were deduced by the intermediates detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). This work will not only contribute to understand the degradation mechanism of pesticides in real water environmental condition, but also promote the development of new technologies for pesticide pollution control as well as environmental remediation.
Developing an excellent photocatalysis system to remove pesticides from water is an urgent problem in current environment purification field. Herein, a Z-scheme WO3/g-C3N4 photocatalyst was prepared by a facile in-situ calcination method, and the photocatalytic activity was investigated for degradation of nitenpyram (NTP) under visible light. The optimal Z-scheme WO3/g-C3N4 photocatalyst displayed the highest rate constant (0.036 min−1), which is about 1.7 and 25 times higher than that of pure g-C3N4 and WO3, respectively. The improvement of photocatalytic performance is attributed to fast transfer of photogenerated carriers in the Z-scheme structure, which are testified by electron spin resonance (ESR) experiments, photocurrent and electrochemical impedance spectra (EIS) measurements. Moreover, the effects of typical water environmental factors on the degradation NTP were systematically studied. And the possible degradation pathways of NTP were deduced by the intermediates detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). This work will not only contribute to understand the degradation mechanism of pesticides in real water environmental condition, but also promote the development of new technologies for pesticide pollution control as well as environmental remediation.
2021, 32(7): 2183-2186
doi: 10.1016/j.cclet.2020.12.007
Abstract:
MicroRNAs are a class of important biomarkers, and the simultaneous detection of multiple miRNAs can provide valuable information about many diseases and biological processes. Amplification-free determination has been developed for the analysis of multiple miRNAs because of its characteristic low cost and high fidelity. Herein, a method for the amplification-free analysis and simultaneous detection of multiple miRNAs based on a so-called pico-HPLC-LIF system is described. In this process, a bare open capillary with an inner diameter of 680 nm is used as a separation column for a sample volume of several hundreds of femtoliters (300 fL), followed by separation and detection. The technique has a zeptomolar limit of detection. The method was applied to detect cellular miRNA from adenocarcinomic human alveolar basal epithelial (A549) cell extracts, and the simultaneous detection of the mir-182, miR-155, and let-7a was achieved. The results showed that the expression of mir-182 and miR-155 was up-regulated and that of let-7a was down-regulated in A549 cells. This method for multiple miRNAs detection is expected to have broad applications in miRNA-based disease diagnosis, prognosis, treatment, and monitoring.
MicroRNAs are a class of important biomarkers, and the simultaneous detection of multiple miRNAs can provide valuable information about many diseases and biological processes. Amplification-free determination has been developed for the analysis of multiple miRNAs because of its characteristic low cost and high fidelity. Herein, a method for the amplification-free analysis and simultaneous detection of multiple miRNAs based on a so-called pico-HPLC-LIF system is described. In this process, a bare open capillary with an inner diameter of 680 nm is used as a separation column for a sample volume of several hundreds of femtoliters (300 fL), followed by separation and detection. The technique has a zeptomolar limit of detection. The method was applied to detect cellular miRNA from adenocarcinomic human alveolar basal epithelial (A549) cell extracts, and the simultaneous detection of the mir-182, miR-155, and let-7a was achieved. The results showed that the expression of mir-182 and miR-155 was up-regulated and that of let-7a was down-regulated in A549 cells. This method for multiple miRNAs detection is expected to have broad applications in miRNA-based disease diagnosis, prognosis, treatment, and monitoring.
2021, 32(7): 2187-2191
doi: 10.1016/j.cclet.2020.12.010
Abstract:
A novel GO modified g-C3N4 nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method. The characterization results reveal that wrinkled GO is deposited between g-C3N4 nanosheets and flower-like BiOBr forming a Z-scheme heterojunction. As a mediator, plicate GO plays a positive role in prompting photogenerated electrons transferring through its sizeable 2D/2D contact surface area. The g-C3N4/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C3N4 and BiOBr in photodegrading tetracycline (TC), whose removal efficiency could reach 96% within 2 h. Besides, g-C3N4/GO/BiOBr composite can reduce Cr(Ⅵ), and simultaneously treat TC and Cr(Ⅵ) combination contaminant under the visible light. The g-C3N4/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments. Further, a feasible mechanism related to the photocatalytic process of g-C3N4/GO/BiOBr is put forward. This study offers a ternary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.
A novel GO modified g-C3N4 nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method. The characterization results reveal that wrinkled GO is deposited between g-C3N4 nanosheets and flower-like BiOBr forming a Z-scheme heterojunction. As a mediator, plicate GO plays a positive role in prompting photogenerated electrons transferring through its sizeable 2D/2D contact surface area. The g-C3N4/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C3N4 and BiOBr in photodegrading tetracycline (TC), whose removal efficiency could reach 96% within 2 h. Besides, g-C3N4/GO/BiOBr composite can reduce Cr(Ⅵ), and simultaneously treat TC and Cr(Ⅵ) combination contaminant under the visible light. The g-C3N4/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments. Further, a feasible mechanism related to the photocatalytic process of g-C3N4/GO/BiOBr is put forward. This study offers a ternary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.
2021, 32(7): 2192-2196
doi: 10.1016/j.cclet.2020.12.036
Abstract:
A label-free and sensitive electrochemical biosensing strategy for a hepatocellular carcinoma biomarker of miRNA-122 has been proposed based on hybridization induced ion-barrier effect on the electroactive sensing interface. First, a bifunctional electroactive electrode with the nanocomposite of Prussian blue (PB) and gold nanoparticles (AuNPs) was prepared through a two-step electrodeposition process. The PB endows the electrode excellent K+-dependent voltammetric signal and the AuNPs act as the matrix for the self-assembly immobilization of the thiolated probe DNA. Upon specific hybridization of probe DNA with the target miRNA-122, the formed double duplex induced the ion-barrier effect, which blocked the diffusion of the K + from the bulk solution to the electrode surface. As a result, the voltammetric signal of the PB on the electrode was surpressed, and thus the target miRNA-122 was monitored. The sensing assay showed that the miRNA-122 could be analyzed in the concentration range from 0.1 fmol/L to 1.0 nmol/L, with a detection limit of 0.021 fmol/L. The practical applicability of the biosensor was also verified by the spiking serum assay.
A label-free and sensitive electrochemical biosensing strategy for a hepatocellular carcinoma biomarker of miRNA-122 has been proposed based on hybridization induced ion-barrier effect on the electroactive sensing interface. First, a bifunctional electroactive electrode with the nanocomposite of Prussian blue (PB) and gold nanoparticles (AuNPs) was prepared through a two-step electrodeposition process. The PB endows the electrode excellent K+-dependent voltammetric signal and the AuNPs act as the matrix for the self-assembly immobilization of the thiolated probe DNA. Upon specific hybridization of probe DNA with the target miRNA-122, the formed double duplex induced the ion-barrier effect, which blocked the diffusion of the K + from the bulk solution to the electrode surface. As a result, the voltammetric signal of the PB on the electrode was surpressed, and thus the target miRNA-122 was monitored. The sensing assay showed that the miRNA-122 could be analyzed in the concentration range from 0.1 fmol/L to 1.0 nmol/L, with a detection limit of 0.021 fmol/L. The practical applicability of the biosensor was also verified by the spiking serum assay.
2021, 32(7): 2197-2202
doi: 10.1016/j.cclet.2020.12.042
Abstract:
The peroxisome proliferator-activated receptor (PPARδ) agonists are reported to improve insulin sensitivity, reduce glucose levels, and alleviate dysfunctional lipid metabolism in animal models of type 2 diabetes mellitus. However, the underlying mechanisms remain incompletely understood. Metabolism plays an essential role in the biological system. Monitoring of metabolic changes in response to disease conditions or drug treatment is critical for better understanding of the pathophysiological mechanisms. In this study, metabolic profiling analysis by gas chromatography-mass spectrometry integrated with targeted analysis by liquid chromatography-mass spectrometry was carried out in plasma samples of db/db diabetic mice after six-week treatment of PPARδ agonist GW501516. GW501516 treatment significantly altered levels of metabolites, such as branched-chain amino acids (BCAAs), BCAA metabolites (3-hydroxyisobutyric acid and 3-hydroxyisovaleric acid), long-chain fatty acids, uric acid and ketone bodies (3-hydroxybutyric acid and 2-hydroxybutyric acid) which are all associated with the impaired systemic insulin sensitivity. The present results indicate the beneficial effect of PPARδ agonist in alleviating insulin resistance of diabetic mice by favorably modulating metabolic profile, thus providing valuable information in understanding the therapeutic potential of PPARδ agonists in correcting metabolic dysfunction in diabetes.
The peroxisome proliferator-activated receptor (PPARδ) agonists are reported to improve insulin sensitivity, reduce glucose levels, and alleviate dysfunctional lipid metabolism in animal models of type 2 diabetes mellitus. However, the underlying mechanisms remain incompletely understood. Metabolism plays an essential role in the biological system. Monitoring of metabolic changes in response to disease conditions or drug treatment is critical for better understanding of the pathophysiological mechanisms. In this study, metabolic profiling analysis by gas chromatography-mass spectrometry integrated with targeted analysis by liquid chromatography-mass spectrometry was carried out in plasma samples of db/db diabetic mice after six-week treatment of PPARδ agonist GW501516. GW501516 treatment significantly altered levels of metabolites, such as branched-chain amino acids (BCAAs), BCAA metabolites (3-hydroxyisobutyric acid and 3-hydroxyisovaleric acid), long-chain fatty acids, uric acid and ketone bodies (3-hydroxybutyric acid and 2-hydroxybutyric acid) which are all associated with the impaired systemic insulin sensitivity. The present results indicate the beneficial effect of PPARδ agonist in alleviating insulin resistance of diabetic mice by favorably modulating metabolic profile, thus providing valuable information in understanding the therapeutic potential of PPARδ agonists in correcting metabolic dysfunction in diabetes.
2021, 32(7): 2203-2206
doi: 10.1016/j.cclet.2020.12.022
Abstract:
With regard to the reaction of higher alcohol synthesis (HAS), the optimizations of activity and selectivity towards C2+ alcohol are restricted by the improper equilibrium in two different CO activation pathways and chain growth capacity. Herein, we find that delibrately controlling the compositions of catalysts is an effective strategy to achieve the equilibrium of CO activation pathways and promote the chain growth. As a result, the optimized Cu0.25Co0.75 alloy catalyst can achieve a large proportion of higher alcohol in alcohol products (C2+OH/MeOH = 4.40), together with high CO conversion of 71.27% and space-time-yield of 147.65 g kg−1 h−1. The mechanistic studies suggest that the good performance of Cu0.25Co0.75 catalyst is attributed to the synergistic effect between alloyed Cu and Co.
With regard to the reaction of higher alcohol synthesis (HAS), the optimizations of activity and selectivity towards C2+ alcohol are restricted by the improper equilibrium in two different CO activation pathways and chain growth capacity. Herein, we find that delibrately controlling the compositions of catalysts is an effective strategy to achieve the equilibrium of CO activation pathways and promote the chain growth. As a result, the optimized Cu0.25Co0.75 alloy catalyst can achieve a large proportion of higher alcohol in alcohol products (C2+OH/MeOH = 4.40), together with high CO conversion of 71.27% and space-time-yield of 147.65 g kg−1 h−1. The mechanistic studies suggest that the good performance of Cu0.25Co0.75 catalyst is attributed to the synergistic effect between alloyed Cu and Co.
2021, 32(7): 2207-2211
doi: 10.1016/j.cclet.2020.12.021
Abstract:
Noble-metal-free photocatalysts with high and stable performance provide an environmentally-friendly and cost-efficient route for green organic synthesis. In this work, CdS nanoparticles with small particle size and different amount were successfully deposited on the surface of covalent organic frameworks (COFs). The deposition of suitable content of CdS on COFs could not only modify the light adsorption ability and the intrinsic electronic properties, but also enhance the photocatalytic activity and cycling performance of CdS for the selective oxidation of aromatic alcohols under visible light. Especially, COF/CdS-3 exhibited the highest yield (97.1%) of benzaldehyde which is approximately 2.5 and 15.9 times as that of parental CdS and COF, respectively. The results show that the combination of CdS and COF can improve the utilization of visible light and the separation of photo-generated charge carriers, and COF with the π-conjugated system as supports for CdS nanoparticles could provide efficient electron transport channels and improve the photocatalytic performance. Therefore, this kind of COF-supported photocatalysts with accelerated photo-induced electrons and charge-carrier separation between semiconductors possesses great potentials in future green organic synthesis.
Noble-metal-free photocatalysts with high and stable performance provide an environmentally-friendly and cost-efficient route for green organic synthesis. In this work, CdS nanoparticles with small particle size and different amount were successfully deposited on the surface of covalent organic frameworks (COFs). The deposition of suitable content of CdS on COFs could not only modify the light adsorption ability and the intrinsic electronic properties, but also enhance the photocatalytic activity and cycling performance of CdS for the selective oxidation of aromatic alcohols under visible light. Especially, COF/CdS-3 exhibited the highest yield (97.1%) of benzaldehyde which is approximately 2.5 and 15.9 times as that of parental CdS and COF, respectively. The results show that the combination of CdS and COF can improve the utilization of visible light and the separation of photo-generated charge carriers, and COF with the π-conjugated system as supports for CdS nanoparticles could provide efficient electron transport channels and improve the photocatalytic performance. Therefore, this kind of COF-supported photocatalysts with accelerated photo-induced electrons and charge-carrier separation between semiconductors possesses great potentials in future green organic synthesis.
2021, 32(7): 2212-2216
doi: 10.1016/j.cclet.2020.12.062
Abstract:
A highly-active, metal-free, carbon-based oxygen reduction reaction (ORR) cathode, i.e., graphitized N-doped carbon felt (GNCF), was prepared, for the first time, by in-situ modifying the doping species of polyacrylonitrile (PAN)-based carbon felt (CF) via a facile annealing process in Ar atmosphere. It was applied for dramatically enhanced organics degradation and electricity generation in a photocatalytic fuel cell (PFC) system. The GNCF showed enhanced specific surface area, improved graphitization and raised ratio of graphitic N, therefore resulting in excellently improved ORR performance compared to the CF. When applying the GNCF as a cathode in a PFC system, the proposed PFC showed significant improvement in degrading various model organic conta minants and outputing electricity simultaneously when compared with the PFC with CF. For instance, the apparent rate constant and electricity output efficiency showed ~10.6 times and ~7.2 times, respectively, improvement when using rhoda mine B as model waste. Further improved performance was also achieved by aeration of air or O2 due to the further enhanced ORR. The proposed PFC was also efficient in a wide pH, and kept outstanding stability in long-term utilization.
A highly-active, metal-free, carbon-based oxygen reduction reaction (ORR) cathode, i.e., graphitized N-doped carbon felt (GNCF), was prepared, for the first time, by in-situ modifying the doping species of polyacrylonitrile (PAN)-based carbon felt (CF) via a facile annealing process in Ar atmosphere. It was applied for dramatically enhanced organics degradation and electricity generation in a photocatalytic fuel cell (PFC) system. The GNCF showed enhanced specific surface area, improved graphitization and raised ratio of graphitic N, therefore resulting in excellently improved ORR performance compared to the CF. When applying the GNCF as a cathode in a PFC system, the proposed PFC showed significant improvement in degrading various model organic conta minants and outputing electricity simultaneously when compared with the PFC with CF. For instance, the apparent rate constant and electricity output efficiency showed ~10.6 times and ~7.2 times, respectively, improvement when using rhoda mine B as model waste. Further improved performance was also achieved by aeration of air or O2 due to the further enhanced ORR. The proposed PFC was also efficient in a wide pH, and kept outstanding stability in long-term utilization.
2021, 32(7): 2217-2221
doi: 10.1016/j.cclet.2020.12.017
Abstract:
Aqueous supercapacitors (SCs) have attracted more and more attention for their safety, fast charge/discharge capability and ultra-long life. However, the application of aqueous SCs is limited by the low working voltage due to the narrow electrochemical stability window (ESW) of water. Herein, we report a new "water in salt" (WIS) electrolyte by dissolving potassium bis (fluorosulfonyl) amide (KFSI) in water with an ultra-high mass molar concentration of 37 mol/kg. The highly concentrated electrolyte can achieve a wide ESW of 2.8 V. The WIS electrolyte enables a safe carbon-based symmetrical supercapacitor to operate stably at 2.3 V with an ultra-long cycle life and excellent rate performance. The energy density reaches 20.5 Wh/kg at 2300 W/kg, and the capacity retention is 83.5% after 50, 000 cycles at a current density of 5 A/g. This new electrolyte will be a promising candidate for future high-voltage aqueous supercapacitors.
Aqueous supercapacitors (SCs) have attracted more and more attention for their safety, fast charge/discharge capability and ultra-long life. However, the application of aqueous SCs is limited by the low working voltage due to the narrow electrochemical stability window (ESW) of water. Herein, we report a new "water in salt" (WIS) electrolyte by dissolving potassium bis (fluorosulfonyl) amide (KFSI) in water with an ultra-high mass molar concentration of 37 mol/kg. The highly concentrated electrolyte can achieve a wide ESW of 2.8 V. The WIS electrolyte enables a safe carbon-based symmetrical supercapacitor to operate stably at 2.3 V with an ultra-long cycle life and excellent rate performance. The energy density reaches 20.5 Wh/kg at 2300 W/kg, and the capacity retention is 83.5% after 50, 000 cycles at a current density of 5 A/g. This new electrolyte will be a promising candidate for future high-voltage aqueous supercapacitors.
2021, 32(7): 2222-2228
doi: 10.1016/j.cclet.2020.11.040
Abstract:
Highly active and low-cost catalytic electrodes for urea oxidation reaction (UOR) are always crucial for exploration of urea fuel cells. Herein, novel york-shell-structural Ni2P/C nanosphere hybrids (Ni2P/C-YS) are rationally constructed via a hydrothermal method and subsequent phosphidation treatment under different temperature ranging from 250 ℃ to 450 ℃ for UOR applications. In the in-situ constructed hollow york-shell structure, the coupling of conductive carbon materials and active Ni2P allows numerous interfaces facilitating the electron transfer and thereby accelerating the catalytic kinetics. The results demonstrate that Ni2P/C-YS-350 nanocomposite can boost the UOR process with a low potential of 1.366 V vs. RHE at a current density of 50 mA/cm2 in alkaline electrolyte and afford the superior durability with negligible potential decay after 23 h. This study presents that the carbon coated Ni2P hybrid with the optimized crystallinities and hollow york-shell configurations can be a promising candidate for application in urea fuel cells.
Highly active and low-cost catalytic electrodes for urea oxidation reaction (UOR) are always crucial for exploration of urea fuel cells. Herein, novel york-shell-structural Ni2P/C nanosphere hybrids (Ni2P/C-YS) are rationally constructed via a hydrothermal method and subsequent phosphidation treatment under different temperature ranging from 250 ℃ to 450 ℃ for UOR applications. In the in-situ constructed hollow york-shell structure, the coupling of conductive carbon materials and active Ni2P allows numerous interfaces facilitating the electron transfer and thereby accelerating the catalytic kinetics. The results demonstrate that Ni2P/C-YS-350 nanocomposite can boost the UOR process with a low potential of 1.366 V vs. RHE at a current density of 50 mA/cm2 in alkaline electrolyte and afford the superior durability with negligible potential decay after 23 h. This study presents that the carbon coated Ni2P hybrid with the optimized crystallinities and hollow york-shell configurations can be a promising candidate for application in urea fuel cells.
2021, 32(7): 2229-2232
doi: 10.1016/j.cclet.2020.12.032
Abstract:
Nanocomposites comprising flexible polymers and high dielectric constant inorganic nanoparticles are considered to be one of the promising candidates for electrostatic capacitor dielectrics. However, the effect of interfacial property on electrical energy storage of dielectric polymer nanocomposites is still not clear. Herein, the role of the polarity of the interfacial region is investigated. For this purpose, three polymers with different polarity, polymethyl methacrylate (PMMA), polyglycidyl methacrylate, and polymethylsulfonyl ethyl methacrylate (PMSEMA) are attached onto BaTiO3 (BT) nanoparticle surface via surface-initiated reversible addition-fragmentation chain transfer polymerization. It is found that the polarity of shell polymers shows an apparent effect on the dielectric and energy storage of dielectric polymer nanocomposites. For example, PMSEMA@BT (shell polymer possesses the highest polarity) increases dielectric loss and decreases the breakdown strength of the nanocomposites, leading to lower energy storage capability. However, PMMA@BT (shell polymer possesses the lowest polarity) can induce higher breakdown strength of the nanocomposites. As a result, the PMMA@BT nanocomposite exhibits the highest electrical energy storage capability among the three nanocomposites. This research provides new insight into the design of core-shell nanofillers for dielectric energy storage applications.
Nanocomposites comprising flexible polymers and high dielectric constant inorganic nanoparticles are considered to be one of the promising candidates for electrostatic capacitor dielectrics. However, the effect of interfacial property on electrical energy storage of dielectric polymer nanocomposites is still not clear. Herein, the role of the polarity of the interfacial region is investigated. For this purpose, three polymers with different polarity, polymethyl methacrylate (PMMA), polyglycidyl methacrylate, and polymethylsulfonyl ethyl methacrylate (PMSEMA) are attached onto BaTiO3 (BT) nanoparticle surface via surface-initiated reversible addition-fragmentation chain transfer polymerization. It is found that the polarity of shell polymers shows an apparent effect on the dielectric and energy storage of dielectric polymer nanocomposites. For example, PMSEMA@BT (shell polymer possesses the highest polarity) increases dielectric loss and decreases the breakdown strength of the nanocomposites, leading to lower energy storage capability. However, PMMA@BT (shell polymer possesses the lowest polarity) can induce higher breakdown strength of the nanocomposites. As a result, the PMMA@BT nanocomposite exhibits the highest electrical energy storage capability among the three nanocomposites. This research provides new insight into the design of core-shell nanofillers for dielectric energy storage applications.
2021, 32(7): 2233-2238
doi: 10.1016/j.cclet.2020.12.030
Abstract:
This study was to investigate the optimal additions of the cellulose decomposition reaction to obtain the most yield of 5-HMF and other furan derivatives in various biphasic systems with FeCl3-CuCl2 mixed catalysts, and explore its depolymerization kinetics. A series of controllable reactions have been performed under mild environmentally friendly atmosphere. The experiment results showed that 49.13 wt% of 5-HMF was the maximum production along with 2.98 wt% other furan derivatives catalyzed by mixed Lewis acid FeCl3-CuCl2 under the two phases which included high concentration NaCl aqueous phase and n-butanol organic phase at 190 ℃ for 45 min. The conclusion suggested that two-phase systems benefited the yield of 5-HMF, furan derivatives via extracting the target products from reaction phase to organic phase to avoid rehydration of 5-HMF. The kinetic calculation revealed the conversion with mixed catalysts had lower reaction apparent activation energy (21.65 kJ/mol, 190-230 ℃) and the reaction rate was faster than that with acid-based catalysts. Based on experiment exploration, the probable mechanism of cellulose decomposition with FeCl3-CuCl2 was proposed.
This study was to investigate the optimal additions of the cellulose decomposition reaction to obtain the most yield of 5-HMF and other furan derivatives in various biphasic systems with FeCl3-CuCl2 mixed catalysts, and explore its depolymerization kinetics. A series of controllable reactions have been performed under mild environmentally friendly atmosphere. The experiment results showed that 49.13 wt% of 5-HMF was the maximum production along with 2.98 wt% other furan derivatives catalyzed by mixed Lewis acid FeCl3-CuCl2 under the two phases which included high concentration NaCl aqueous phase and n-butanol organic phase at 190 ℃ for 45 min. The conclusion suggested that two-phase systems benefited the yield of 5-HMF, furan derivatives via extracting the target products from reaction phase to organic phase to avoid rehydration of 5-HMF. The kinetic calculation revealed the conversion with mixed catalysts had lower reaction apparent activation energy (21.65 kJ/mol, 190-230 ℃) and the reaction rate was faster than that with acid-based catalysts. Based on experiment exploration, the probable mechanism of cellulose decomposition with FeCl3-CuCl2 was proposed.
2021, 32(7): 2239-2242
doi: 10.1016/j.cclet.2020.12.037
Abstract:
Nowadays, Cu-based materials have attracted extensive attention as electrocatalysts, while the inherent reason of the filling of high anti-bonding state of Cu d band (3d104s1) makes it difficult to hybridize with O 2p band of oxygen intermediates during the adsorption process of oxygen evolution reaction (OER). To increase the efficiency of Cu-based electrocatalysts, efforts have been made to optimize the electronic structures and to create surface defects and hierarchical nanostructures with more exposed accessible active sites. Herein, we report a facile method for preparing CuO electrocatalysts with hierarchical nanostructures using the Cu-alanine complex as a precursor through room-temperature chemical precipitation and subsequent calcination in air. Investigations of products obtained at different calcination temperatures reveal the relationship between OER activities and the material characteristics such as specific surface areas, crystal growth orientations, and element components. The product obtained at 500 ℃ exhibits the smallest overpotential of 290 mV in 1.0 mol/L KOH for electrocatalyzing OER. Combining with various characterizations of CuO electrocatalysts after OER activities, the possible catalytic mechanism and the influence factors of their OER performance are also discussed.
Nowadays, Cu-based materials have attracted extensive attention as electrocatalysts, while the inherent reason of the filling of high anti-bonding state of Cu d band (3d104s1) makes it difficult to hybridize with O 2p band of oxygen intermediates during the adsorption process of oxygen evolution reaction (OER). To increase the efficiency of Cu-based electrocatalysts, efforts have been made to optimize the electronic structures and to create surface defects and hierarchical nanostructures with more exposed accessible active sites. Herein, we report a facile method for preparing CuO electrocatalysts with hierarchical nanostructures using the Cu-alanine complex as a precursor through room-temperature chemical precipitation and subsequent calcination in air. Investigations of products obtained at different calcination temperatures reveal the relationship between OER activities and the material characteristics such as specific surface areas, crystal growth orientations, and element components. The product obtained at 500 ℃ exhibits the smallest overpotential of 290 mV in 1.0 mol/L KOH for electrocatalyzing OER. Combining with various characterizations of CuO electrocatalysts after OER activities, the possible catalytic mechanism and the influence factors of their OER performance are also discussed.
2021, 32(7): 2243-2248
doi: 10.1016/j.cclet.2020.12.050
Abstract:
The development of low-cost and highly efficient bifunctional electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of critical importance for clean energy devices such as fuel cells and metal-air batteries. Herein, a sophisticated nanostructure composed of CoS, Co and MoC nanoparticles incorporated in N and S dual-doped porous carbon nanofibers (CoS/Co/MoC-N, S-PCNFs) as a high-efficiency bifunctional electrocatalyst is designed and synthesized via an efficient multi-step strategy. The as-prepared CoS/Co/MoC-N, S-PCNFs exhibit a positive half-wave potential (E1/2) of 0.871 V for ORR and a low overpotential of 289 mV at 10 mA/cm2 for OER, outperforming the non-noble metal-based catalysts reported. Furthermore, the assembled Zn-air battery based on CoS/Co/MoC-N, S-PCNFs delivers an excellent power density (169.1 mW/cm2), a large specific capacity (819.3 mAh/g) and robust durability, demonstrating the great potential of the as-developed bifunctional electrocatalyst in practical applications. This work is expected to inspire the design of advanced bifunctional nonprecious metal-based electrocatalysts for energy storage.
The development of low-cost and highly efficient bifunctional electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of critical importance for clean energy devices such as fuel cells and metal-air batteries. Herein, a sophisticated nanostructure composed of CoS, Co and MoC nanoparticles incorporated in N and S dual-doped porous carbon nanofibers (CoS/Co/MoC-N, S-PCNFs) as a high-efficiency bifunctional electrocatalyst is designed and synthesized via an efficient multi-step strategy. The as-prepared CoS/Co/MoC-N, S-PCNFs exhibit a positive half-wave potential (E1/2) of 0.871 V for ORR and a low overpotential of 289 mV at 10 mA/cm2 for OER, outperforming the non-noble metal-based catalysts reported. Furthermore, the assembled Zn-air battery based on CoS/Co/MoC-N, S-PCNFs delivers an excellent power density (169.1 mW/cm2), a large specific capacity (819.3 mAh/g) and robust durability, demonstrating the great potential of the as-developed bifunctional electrocatalyst in practical applications. This work is expected to inspire the design of advanced bifunctional nonprecious metal-based electrocatalysts for energy storage.
2021, 32(7): 2249-2253
doi: 10.1016/j.cclet.2020.12.051
Abstract:
Lithium-sulfur battery is strongly considered as the most promising next-generation energy storage system because of the high theoretical specific capacity. The serious "shuttle effect" and sluggish reaction kinetic limited the commercial application of lithium-sulfur battery. Many heterostructures were applied to accelerate polysulfides conversion and suppress their migration in lithium-sulfur batteries. Nevertheless, the effect of the interface in heterostructure was not clear. Here, the Co2B@MXene heterostructure is synthesized through chemical reactions at room temperature and employed as the interlayer material for Li-S batteries. The theoretical calculations and experimental results indicate that the interfacial electronic interaction of Co2B@MXene induce the transfer of electrons from Co2B to MXene, enhancing the catalytic ability and favoring fast redox kinetics of the polysulfides, and the theoretical calculations also reveal the underlying mechanisms for the electron transfer is that the two materials have different Fermi energy levels. The cell with Co2B@MXene exhibits a high initial capacity of 1577 mAh/g at 0.1 C and an ultralow capacity decay of 0.0088% per cycle over 2000 cycles at 2 C. Even at 5.1 mg/cm2 of sulfur loading, the cell with Co2B@MXene delivers 5.2 mAh/cm2 at 0.2 C.
Lithium-sulfur battery is strongly considered as the most promising next-generation energy storage system because of the high theoretical specific capacity. The serious "shuttle effect" and sluggish reaction kinetic limited the commercial application of lithium-sulfur battery. Many heterostructures were applied to accelerate polysulfides conversion and suppress their migration in lithium-sulfur batteries. Nevertheless, the effect of the interface in heterostructure was not clear. Here, the Co2B@MXene heterostructure is synthesized through chemical reactions at room temperature and employed as the interlayer material for Li-S batteries. The theoretical calculations and experimental results indicate that the interfacial electronic interaction of Co2B@MXene induce the transfer of electrons from Co2B to MXene, enhancing the catalytic ability and favoring fast redox kinetics of the polysulfides, and the theoretical calculations also reveal the underlying mechanisms for the electron transfer is that the two materials have different Fermi energy levels. The cell with Co2B@MXene exhibits a high initial capacity of 1577 mAh/g at 0.1 C and an ultralow capacity decay of 0.0088% per cycle over 2000 cycles at 2 C. Even at 5.1 mg/cm2 of sulfur loading, the cell with Co2B@MXene delivers 5.2 mAh/cm2 at 0.2 C.
2021, 32(7): 2254-2258
doi: 10.1016/j.cclet.2020.12.056
Abstract:
Lithium metal has a very outstanding theoretical capacity (3860 mAh/g) and is one of the most superior anode materials for high energy density batteries. However, the uncontrollable dendrite growth and the formation of "dead lithium" are the important hidden dangers of short cycle life and low safety. However, the uncontrollable dendrite growth and the formation of dead lithium leads to short cycle life and hidden danger, which hinder its practical application. Controlling the nucleation and growth process of lithium is an effective strategy to inhibit lithium dendrite. Herein, a simple in situ self-catalytic method is used to construct nitrogen doped carbon nanotube arrays on stainless steel mesh (N-CNT@SS) as a lithium composite anode. The N-doped CNTs provide a great number of N-functional groups, which enhance the lithiophilic of anode and provide a large number of uniform nucleation sites, hence it has excellent structural stability for cycles. The arrays provide neat lithium-ion transport channels to uniform lithium-ion flux and inhibits dendrite generation, revealed by the COMSOL multi-physics concentration field simulation. The N-CNT@SS composite anode sustain stable at 98.9% over 300 cycles at 1 mA/cm2. N-CNT@SS as the anode is coupled LiFePO4 (LFP) as the cathode construct a full battery, demonstrating excellent cycling stability with a capacity of 152.33 mAh/g and capacity retaining ratio of 95.4% after 100 cycles at 0.5 C.
Lithium metal has a very outstanding theoretical capacity (3860 mAh/g) and is one of the most superior anode materials for high energy density batteries. However, the uncontrollable dendrite growth and the formation of "dead lithium" are the important hidden dangers of short cycle life and low safety. However, the uncontrollable dendrite growth and the formation of dead lithium leads to short cycle life and hidden danger, which hinder its practical application. Controlling the nucleation and growth process of lithium is an effective strategy to inhibit lithium dendrite. Herein, a simple in situ self-catalytic method is used to construct nitrogen doped carbon nanotube arrays on stainless steel mesh (N-CNT@SS) as a lithium composite anode. The N-doped CNTs provide a great number of N-functional groups, which enhance the lithiophilic of anode and provide a large number of uniform nucleation sites, hence it has excellent structural stability for cycles. The arrays provide neat lithium-ion transport channels to uniform lithium-ion flux and inhibits dendrite generation, revealed by the COMSOL multi-physics concentration field simulation. The N-CNT@SS composite anode sustain stable at 98.9% over 300 cycles at 1 mA/cm2. N-CNT@SS as the anode is coupled LiFePO4 (LFP) as the cathode construct a full battery, demonstrating excellent cycling stability with a capacity of 152.33 mAh/g and capacity retaining ratio of 95.4% after 100 cycles at 0.5 C.
2021, 32(7): 2259-2262
doi: 10.1016/j.cclet.2020.12.052
Abstract:
2D halide perovskites have emerged as promising materials because of their stability and passivation effect in perovskite solar cells (PSCs). However, the introduction of bulky organic ammonium cations from 2D halide perovskites would decrease the device performance generally compared to the traditional 3D MAPbI3. Incorporation of ultrathin 2D halide perovskite nanosheets (NSs) with 3D MAPbI3 could address this issue. Herein, we report a rationally designed PSCs with dimensional graded 3D/2D MAPbI3/(PEA)2PbI4 heterojunction, in which 2D (PEA)2PbI4 NSs were synthesized and incorporated between 3D MAPbI3 and hole-transporting layer. Besides the significantly improved stability, a notable increasement in power conversion efficiency (PCE) of 20% was obtained for the 3D/2D perovskite solar cells due to the favourable band alignment among (PEA)2PbI4 NSs and the other components. The graded structure of MAPbI3/(PEA)2PbI4 would upshift the energy level continuously, which enhances the hole extraction efficiency thus reduces the interface charge recombination, leading to the increasements of VOC from 1.04 V to 1.07 V, JSC from 21.81 mA/cm2 to 23.15 mA/cm2 and the fill factor from 67.89% to 74.78%, and therefore an overall PCE of 18.53%.
2D halide perovskites have emerged as promising materials because of their stability and passivation effect in perovskite solar cells (PSCs). However, the introduction of bulky organic ammonium cations from 2D halide perovskites would decrease the device performance generally compared to the traditional 3D MAPbI3. Incorporation of ultrathin 2D halide perovskite nanosheets (NSs) with 3D MAPbI3 could address this issue. Herein, we report a rationally designed PSCs with dimensional graded 3D/2D MAPbI3/(PEA)2PbI4 heterojunction, in which 2D (PEA)2PbI4 NSs were synthesized and incorporated between 3D MAPbI3 and hole-transporting layer. Besides the significantly improved stability, a notable increasement in power conversion efficiency (PCE) of 20% was obtained for the 3D/2D perovskite solar cells due to the favourable band alignment among (PEA)2PbI4 NSs and the other components. The graded structure of MAPbI3/(PEA)2PbI4 would upshift the energy level continuously, which enhances the hole extraction efficiency thus reduces the interface charge recombination, leading to the increasements of VOC from 1.04 V to 1.07 V, JSC from 21.81 mA/cm2 to 23.15 mA/cm2 and the fill factor from 67.89% to 74.78%, and therefore an overall PCE of 18.53%.
2021, 32(7): 2263-2268
doi: 10.1016/j.cclet.2020.12.015
Abstract:
The development of active, low-cost and durable bifunctional electrocatalysts toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are important for overall water splitting. Here, well-defined arrays of vanadium-iron bimetal organic frameworks (VFe-MOF) with controllable stoichiometry have been successfully prepared on nickel foam (NF). The as-fabricated VFe-MOF@NF electrode exhibits excellent electrocatalytic activity and durability for OER and HER in alkaline medium. The material's overpotentials of 10 mA/cm2 are 246 mV for OER and 147 mV for HER, respectively. The electrolyzer made from the VFe-MOF@NF electrodes as both the cathode and anode in 1 mol/L KOH needs only a voltage of 1.61 V to reach a current density of 10 mA/cm2. The superior performance of VFe-MOF@NF can be attributed to the morphological control and electronic regulation of the bimetals, that is, 1) the exposure of the active sites at electrocatalyst/electrolyte interfaces due to the array structure; 2) the synergistic effect of vanadium and iron metals on electro-catalyzing the overall water splitting.
The development of active, low-cost and durable bifunctional electrocatalysts toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are important for overall water splitting. Here, well-defined arrays of vanadium-iron bimetal organic frameworks (VFe-MOF) with controllable stoichiometry have been successfully prepared on nickel foam (NF). The as-fabricated VFe-MOF@NF electrode exhibits excellent electrocatalytic activity and durability for OER and HER in alkaline medium. The material's overpotentials of 10 mA/cm2 are 246 mV for OER and 147 mV for HER, respectively. The electrolyzer made from the VFe-MOF@NF electrodes as both the cathode and anode in 1 mol/L KOH needs only a voltage of 1.61 V to reach a current density of 10 mA/cm2. The superior performance of VFe-MOF@NF can be attributed to the morphological control and electronic regulation of the bimetals, that is, 1) the exposure of the active sites at electrocatalyst/electrolyte interfaces due to the array structure; 2) the synergistic effect of vanadium and iron metals on electro-catalyzing the overall water splitting.
2021, 32(7): 2269-2273
doi: 10.1016/j.cclet.2020.12.059
Abstract:
In this paper, the process of ammonia borane (AB) hydrolysis generate H2 on the transition metal Fe@Co core-shell structure has been obtained. According to the different roles played by H2O molecules and the number of H2O molecules involved, there are three schemes of reaction paths. Route Ⅰ does not involve the dissociation of H2O molecules and all H atoms come from AB. Moreover, the H2O molecule has no effect on the breaking of the BH bond or the NH bond. The reaction absorbs more heat during the formation of the second and third H2 molecules. Route Ⅱ includes the dissociation of H2O molecules and the cleavage of BH or NH bonds, respectively, and the reaction shows a slight exotherm. Route Ⅲ started from the break of the BN bond and obtained 3H2 molecules through the participation of different numbers of H2O molecules. After multiple comparative analyses, the optimal hydrolysis reaction path has been obtained, and the reaction process can proceed spontaneously at room temperature.
In this paper, the process of ammonia borane (AB) hydrolysis generate H2 on the transition metal Fe@Co core-shell structure has been obtained. According to the different roles played by H2O molecules and the number of H2O molecules involved, there are three schemes of reaction paths. Route Ⅰ does not involve the dissociation of H2O molecules and all H atoms come from AB. Moreover, the H2O molecule has no effect on the breaking of the BH bond or the NH bond. The reaction absorbs more heat during the formation of the second and third H2 molecules. Route Ⅱ includes the dissociation of H2O molecules and the cleavage of BH or NH bonds, respectively, and the reaction shows a slight exotherm. Route Ⅲ started from the break of the BN bond and obtained 3H2 molecules through the participation of different numbers of H2O molecules. After multiple comparative analyses, the optimal hydrolysis reaction path has been obtained, and the reaction process can proceed spontaneously at room temperature.
2021, 32(7): 2274-2278
doi: 10.1016/j.cclet.2021.03.006
Abstract:
The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have reached 18% recently, which have already met the demand of practical application. However, these outstanding results were generally achieved with donor-acceptor (D-A) type copolymer donors, which can hardly fulfill the low-cost large-scale production due to their complicated synthesis processes. Therefore, developing polymer donors with simple chemical structures is urgent for realizing low-cost OSCs. Polythiophene (PT) derivatives are currently regarded as promising candidates for such kind of donor materials, which has been illustrated in many works. In this work, two new alkylthio substituted PT derivatives, P301 and P302, were synthesized and tested as donors in the OSCs using Y5 as the acceptor. In comparison, the introduction of fluorine atoms on the backbone of P302 can not only downshift the energy levels, but also greatly improve the phase separation morphologies of the active layers, which is ascribed to the enhanced aggregation effect and the reduced miscibility with the non-fullerene acceptor. As a result, the P302:Y5-based OSC exhibits a significantly improved PCE of 9.65% than that of P301:Y5-based one, indicating the important role of fluorination in the construction of efficient PT derivative donors.
The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have reached 18% recently, which have already met the demand of practical application. However, these outstanding results were generally achieved with donor-acceptor (D-A) type copolymer donors, which can hardly fulfill the low-cost large-scale production due to their complicated synthesis processes. Therefore, developing polymer donors with simple chemical structures is urgent for realizing low-cost OSCs. Polythiophene (PT) derivatives are currently regarded as promising candidates for such kind of donor materials, which has been illustrated in many works. In this work, two new alkylthio substituted PT derivatives, P301 and P302, were synthesized and tested as donors in the OSCs using Y5 as the acceptor. In comparison, the introduction of fluorine atoms on the backbone of P302 can not only downshift the energy levels, but also greatly improve the phase separation morphologies of the active layers, which is ascribed to the enhanced aggregation effect and the reduced miscibility with the non-fullerene acceptor. As a result, the P302:Y5-based OSC exhibits a significantly improved PCE of 9.65% than that of P301:Y5-based one, indicating the important role of fluorination in the construction of efficient PT derivative donors.
2021, 32(7): 2279-2282
doi: 10.1016/j.cclet.2021.01.003
Abstract:
Hematite (α-Fe2O3) is a promising photoanode for photoelectrochemical (PEC) water splitting. However, the severe charge recombination and sluggish water oxidation kinetics extremely limit its use in photohydrogen conversion. Herein, a co-activation strategy is proposed, namely through phosphorus (P) doping and the loading of CoAl-layered double hydroxides (CoAl-LDHs) cocatalysts. Unexpectedly, the integrated system, CoAl-LDHs/P-Fe2O3 photoanode, exhibits an outstanding photocurrent density of 1.56 mA/cm2 at 1.23 V (vs. reversible hydrogen electrode, RHE), under AM 1.5 G, which is 2.6 times of pure α-Fe2O3. Systematic studies reveal that the remarkable PEC performance is attributed to accelerated surface OER kinetics and enhanced carrier separation efficiency. This work provides a feasible strategy to enhance the PEC performance of hematite photoanodes.
Hematite (α-Fe2O3) is a promising photoanode for photoelectrochemical (PEC) water splitting. However, the severe charge recombination and sluggish water oxidation kinetics extremely limit its use in photohydrogen conversion. Herein, a co-activation strategy is proposed, namely through phosphorus (P) doping and the loading of CoAl-layered double hydroxides (CoAl-LDHs) cocatalysts. Unexpectedly, the integrated system, CoAl-LDHs/P-Fe2O3 photoanode, exhibits an outstanding photocurrent density of 1.56 mA/cm2 at 1.23 V (vs. reversible hydrogen electrode, RHE), under AM 1.5 G, which is 2.6 times of pure α-Fe2O3. Systematic studies reveal that the remarkable PEC performance is attributed to accelerated surface OER kinetics and enhanced carrier separation efficiency. This work provides a feasible strategy to enhance the PEC performance of hematite photoanodes.
2021, 32(7): 2283-2286
doi: 10.1016/j.cclet.2021.01.041
Abstract:
Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H2 energy by semiconductors. However, the band structure of many semiconductors cannot satisfy the requirement of H2 and O2 production at the same time. Herein, we illustrate that carbon dots (CDs)/Bi2WO6 photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent. In this complex photocatalytic system, the photo-potential provided by CDs makes the CDs/Bi2WO6 (C-BWO) composite could satisfy the band structure conditions for overall water photo-splitting. The C-BWO composite (3 wt% CDs content) exhibits optimized hydrogen evolution (oxygen evolution) of 0.28 μmol/h (0.12 μmol/h) with an approximate 2:1 (H2: O2) stoichiometry at normal pressure. We further employed the in-situ transient photovoltage (TPV) technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst.
Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H2 energy by semiconductors. However, the band structure of many semiconductors cannot satisfy the requirement of H2 and O2 production at the same time. Herein, we illustrate that carbon dots (CDs)/Bi2WO6 photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent. In this complex photocatalytic system, the photo-potential provided by CDs makes the CDs/Bi2WO6 (C-BWO) composite could satisfy the band structure conditions for overall water photo-splitting. The C-BWO composite (3 wt% CDs content) exhibits optimized hydrogen evolution (oxygen evolution) of 0.28 μmol/h (0.12 μmol/h) with an approximate 2:1 (H2: O2) stoichiometry at normal pressure. We further employed the in-situ transient photovoltage (TPV) technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst.
2021, 32(7): 2287-2291
doi: 10.1016/j.cclet.2021.01.039
Abstract:
Recently, photodynamic therapy (PDT) has been extensively applied in clinical and coadjuvant treatment of various kinds of tumors. However, the photosensitizer (PS) of PDT still lack of high production of singlet oxygen (1O2), low cytotoxicity and high biocompatibility. Herein, we propose a facile method for establishing a new core-shell structured Sn nanocluster@carbon dots (CDs) PS. Firstly, Sn4+@S-CDs complex is synthesized using the sulfur-doped CDs (S-CDs) and SnCl4 as raw materials, and subsequently the new PS (Sn nanocluster@CDs) is obtained after vaporization of Sn4+@S-CDs solution. Remarkably, the obtained Sn nanocluster@CDs show an enhanced fluorescence as well as a higher 1O2 quantum yield (QY) than S-CDs. The high 1O2 QY (58.3%) irradiated by the LED light (400–700 nm, 40 mW/cm2), induce the reduction of 4T1 cancer cells viability by 25%. More intriguingly, no visible damage happens to healthy cells, with little impact on liver tissue due to renal excretion, both in vitro and in vivo experiments demonstrate that Sn nanocluster@CDs may become a promising PS, owning a high potential for application in PDT.
Recently, photodynamic therapy (PDT) has been extensively applied in clinical and coadjuvant treatment of various kinds of tumors. However, the photosensitizer (PS) of PDT still lack of high production of singlet oxygen (1O2), low cytotoxicity and high biocompatibility. Herein, we propose a facile method for establishing a new core-shell structured Sn nanocluster@carbon dots (CDs) PS. Firstly, Sn4+@S-CDs complex is synthesized using the sulfur-doped CDs (S-CDs) and SnCl4 as raw materials, and subsequently the new PS (Sn nanocluster@CDs) is obtained after vaporization of Sn4+@S-CDs solution. Remarkably, the obtained Sn nanocluster@CDs show an enhanced fluorescence as well as a higher 1O2 quantum yield (QY) than S-CDs. The high 1O2 QY (58.3%) irradiated by the LED light (400–700 nm, 40 mW/cm2), induce the reduction of 4T1 cancer cells viability by 25%. More intriguingly, no visible damage happens to healthy cells, with little impact on liver tissue due to renal excretion, both in vitro and in vivo experiments demonstrate that Sn nanocluster@CDs may become a promising PS, owning a high potential for application in PDT.
2021, 32(7): 2292-2296
doi: 10.1016/j.cclet.2021.02.005
Abstract:
Carbon dots (Cdots) has been proved to possess the catalytic decomposition of H2O2 in the photocatalytic system. It is a potential photo-Fenton catalyst. Since multiple emissive Cdots have different light response range. There is rarely investigation on the performance of Cdots based photo-Fenton on the light wavelength. Herein, blue, green and red emissive carbon dots were synthesized from the different ratio of o-phenylenediamine and catechol by the solvothermal method. They exhibit different light adsorption range from UV to visible light. Furthermore, the photo-Fenton reactivity of Cdots was studied for catalyzing the decomposition of H2O2 to generate free hydroxyl radicals and consequently applying for the removal of methyl blue. The results exhibit that Cdots with the broader light adsorption rang possess the stronger catalytic activity for the photo-Fenton reaction. The H2O2 decomposition rate of red emissive Cdots is 0.074 min−1, which is 2.64 and 1.46 times than the blue and green emissive Cdots, respectively. And the radical detection results confirm that the photo-Fenton happens in the reaction. In addition, the Cdots photo-Fenton can be carried out in the broad pH range from acidic to basic solution, which has a great potential to treat wastewater in the neutral system.
Carbon dots (Cdots) has been proved to possess the catalytic decomposition of H2O2 in the photocatalytic system. It is a potential photo-Fenton catalyst. Since multiple emissive Cdots have different light response range. There is rarely investigation on the performance of Cdots based photo-Fenton on the light wavelength. Herein, blue, green and red emissive carbon dots were synthesized from the different ratio of o-phenylenediamine and catechol by the solvothermal method. They exhibit different light adsorption range from UV to visible light. Furthermore, the photo-Fenton reactivity of Cdots was studied for catalyzing the decomposition of H2O2 to generate free hydroxyl radicals and consequently applying for the removal of methyl blue. The results exhibit that Cdots with the broader light adsorption rang possess the stronger catalytic activity for the photo-Fenton reaction. The H2O2 decomposition rate of red emissive Cdots is 0.074 min−1, which is 2.64 and 1.46 times than the blue and green emissive Cdots, respectively. And the radical detection results confirm that the photo-Fenton happens in the reaction. In addition, the Cdots photo-Fenton can be carried out in the broad pH range from acidic to basic solution, which has a great potential to treat wastewater in the neutral system.
2021, 32(7): 2297-2300
doi: 10.1016/j.cclet.2021.02.016
Abstract:
Borylative cyclization of E-3-arylallyl carbamoyl chlorides is achieved through copper catalyzed intramolecular carboboration with B2pin2. 2-Aryl-3-boryl-γ-lactams are formed with exclusive cis-diastereoselectivity. CuBr-Dppp combination gives the best outcomes. The substrate scope is profiled.
Borylative cyclization of E-3-arylallyl carbamoyl chlorides is achieved through copper catalyzed intramolecular carboboration with B2pin2. 2-Aryl-3-boryl-γ-lactams are formed with exclusive cis-diastereoselectivity. CuBr-Dppp combination gives the best outcomes. The substrate scope is profiled.
2021, 32(7): 2301-2304
doi: 10.1016/j.cclet.2021.02.020
Abstract:
Recognition features of glycine (Gly) with cucurbit[5]uril (Q[5]) and cucurbit[6]uril (Q[6]) both in aqueous solution and solid state were investigated by 1H NMR spectroscopy and X-ray crystallography. 1H NMR data indicate that the Gly is located outside of the portals of the Q[5], exhibiting exo binding with the Q[5]. In the case of the Q[6], the Gly shows endo binding or a dual binding mode (endo and exo binding) with the host, which depends on the amount of the host in the aqueous solution. X-ray crystallography clearly display that the Gly forms 2:1 exclusion complex with the Q[5], and 2:1 inclusion complex with the Q[6]. Interestingly, hydrogen bondings between the encapsulated Gly molecules in the Q[6] were observed.
Recognition features of glycine (Gly) with cucurbit[5]uril (Q[5]) and cucurbit[6]uril (Q[6]) both in aqueous solution and solid state were investigated by 1H NMR spectroscopy and X-ray crystallography. 1H NMR data indicate that the Gly is located outside of the portals of the Q[5], exhibiting exo binding with the Q[5]. In the case of the Q[6], the Gly shows endo binding or a dual binding mode (endo and exo binding) with the host, which depends on the amount of the host in the aqueous solution. X-ray crystallography clearly display that the Gly forms 2:1 exclusion complex with the Q[5], and 2:1 inclusion complex with the Q[6]. Interestingly, hydrogen bondings between the encapsulated Gly molecules in the Q[6] were observed.
2021, 32(7): 2305-2308
doi: 10.1016/j.cclet.2021.02.021
Abstract:
Chiral α-substituted 1, 3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals. However, catalytic asymmetric approaches have been rarely developed. Here, a redox deracemization technology is adopted to address the catalytic asymmetric synthesis. A broad range of α-aryl substituted 1, 3-dihydroisobenzofurans are effectively deracemized in high efficiency with excellent ee. α-Alkynyl substituted ethers were also compatible with the deracemization technology.
Chiral α-substituted 1, 3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals. However, catalytic asymmetric approaches have been rarely developed. Here, a redox deracemization technology is adopted to address the catalytic asymmetric synthesis. A broad range of α-aryl substituted 1, 3-dihydroisobenzofurans are effectively deracemized in high efficiency with excellent ee. α-Alkynyl substituted ethers were also compatible with the deracemization technology.
2021, 32(7): 2309-2312
doi: 10.1016/j.cclet.2021.02.025
Abstract:
A novel route for tandem C–C/C–N formation, annulation and aromatization of hydrazones with 1, 2-dichloroethane to synthesize 1H-pyrazoles has been developed. Furthermore, the 1, 2-dichloroethane serves as alkylation reagent in good to excellent yields. This methodology features mild reaction conditions and good functional group tolerance, providing a direct approach for the preparation of 1H-pyrazoles.
A novel route for tandem C–C/C–N formation, annulation and aromatization of hydrazones with 1, 2-dichloroethane to synthesize 1H-pyrazoles has been developed. Furthermore, the 1, 2-dichloroethane serves as alkylation reagent in good to excellent yields. This methodology features mild reaction conditions and good functional group tolerance, providing a direct approach for the preparation of 1H-pyrazoles.
2021, 32(7): 2313-2316
doi: 10.1016/j.cclet.2021.02.026
Abstract:
When treated with an alkoxide base like t-BuOK in aprotic solvent, N-diphenylmethyl imino oxindoles, made conveniently through condensation of corresponding isatins with N-diphenylmethyl amine, are deprotonated to form azaallyl anions. Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles. Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles. The overall transformation equals to an umpolung process at the C3 of isatins.
When treated with an alkoxide base like t-BuOK in aprotic solvent, N-diphenylmethyl imino oxindoles, made conveniently through condensation of corresponding isatins with N-diphenylmethyl amine, are deprotonated to form azaallyl anions. Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles. Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles. The overall transformation equals to an umpolung process at the C3 of isatins.
2021, 32(7): 2317-2321
doi: 10.1016/j.cclet.2020.12.019
Abstract:
Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes, however high-power light sources are generally necessary to initiate photocatalytic reaction. In this work, we employed an excellent photocatalyst of Bi2WO6 with visible light harvest and meanwhile an intrinsic ferroelectricity, which realized the efficient degradation of organic dye via the synergetic photopiezocatalysis. Through coupling the illumination by a low-power (9 W) LED and the ultrasonic vibration (120 W) by an ultrasonic cleaner, the nanoflower-like Bi2WO6 composed of ultrathin nanosheets showed a much more enhanced photopiezocatalysis performance for purification of organic dye than the individual photocatalysis and piezocatalysis. Furthermore, the high mineralization efficiency and the good durability of the Bi2WO6 catalyst were demonstrated. The possible mechanism of photopiezocatalysis was finally proposed, where the ultrasound-induced piezoelectric field in Bi2WO6 drove photo-generated electrons and holes to diffuse along opposite directions, consequently promoting the separation efficiency of charge carriers. This work indicates that the synergetic photopiezocatalysis by coupling irradiation and ultrasonic vibration is a promising strategy to purify organic pollutants in wastewater.
Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes, however high-power light sources are generally necessary to initiate photocatalytic reaction. In this work, we employed an excellent photocatalyst of Bi2WO6 with visible light harvest and meanwhile an intrinsic ferroelectricity, which realized the efficient degradation of organic dye via the synergetic photopiezocatalysis. Through coupling the illumination by a low-power (9 W) LED and the ultrasonic vibration (120 W) by an ultrasonic cleaner, the nanoflower-like Bi2WO6 composed of ultrathin nanosheets showed a much more enhanced photopiezocatalysis performance for purification of organic dye than the individual photocatalysis and piezocatalysis. Furthermore, the high mineralization efficiency and the good durability of the Bi2WO6 catalyst were demonstrated. The possible mechanism of photopiezocatalysis was finally proposed, where the ultrasound-induced piezoelectric field in Bi2WO6 drove photo-generated electrons and holes to diffuse along opposite directions, consequently promoting the separation efficiency of charge carriers. This work indicates that the synergetic photopiezocatalysis by coupling irradiation and ultrasonic vibration is a promising strategy to purify organic pollutants in wastewater.
2021, 32(7): 2322-2326
doi: 10.1016/j.cclet.2021.01.045
Abstract:
Nucleic acids with G4 elements play a role in the formation of aggregates involved in intracellular phase transitions. Our previous studies suggest that different forms of DNA could act as an accelerating template in Cu/Zn superoxide dismutase (SOD1) aggregation. Here, we examined the regulation of formation and cytotoxicity of the SOD1 aggregates by single-stranded 12-mer deoxynucleotide oligomers (dN)12 (N = A, T, G, C; ssDNAs) under acidic conditions. The ssDNAs can be divided into two groups based on their roles in SOD1 binding, exposure of hydrophobic clusters in SOD1, accelerated formation, morphology and cytotoxicity of SOD1 aggregates. G-quadruplexes convert SOD1 into fibrillar aggregates as a template, a fact which was observed for the first time in the nucleic acid regulation of protein aggregation. Moreover, the fibrillar or fibril-like SOD1 species with a G-quadruplex provided by (dG)12 were less toxic than the amorphous species with (dN)12 (N = A, T). This study not only indicates that both morphology and cytotoxicity of protein aggregates can be regulated by the protein-bound DNAs, but also help us understand roles of nucleic aid G-quadruplexes in the formation of aggregates and membraneless organelles involved in intracellular phase transitions.
Nucleic acids with G4 elements play a role in the formation of aggregates involved in intracellular phase transitions. Our previous studies suggest that different forms of DNA could act as an accelerating template in Cu/Zn superoxide dismutase (SOD1) aggregation. Here, we examined the regulation of formation and cytotoxicity of the SOD1 aggregates by single-stranded 12-mer deoxynucleotide oligomers (dN)12 (N = A, T, G, C; ssDNAs) under acidic conditions. The ssDNAs can be divided into two groups based on their roles in SOD1 binding, exposure of hydrophobic clusters in SOD1, accelerated formation, morphology and cytotoxicity of SOD1 aggregates. G-quadruplexes convert SOD1 into fibrillar aggregates as a template, a fact which was observed for the first time in the nucleic acid regulation of protein aggregation. Moreover, the fibrillar or fibril-like SOD1 species with a G-quadruplex provided by (dG)12 were less toxic than the amorphous species with (dN)12 (N = A, T). This study not only indicates that both morphology and cytotoxicity of protein aggregates can be regulated by the protein-bound DNAs, but also help us understand roles of nucleic aid G-quadruplexes in the formation of aggregates and membraneless organelles involved in intracellular phase transitions.
2021, 32(7): 2327-2332
doi: 10.1016/j.cclet.2020.11.021
Abstract:
Exorbitant aldosterone is closely associated with various severe diseases, including congestive heart failure and chronic kidney disease. As aldosterone synthase is the pivotal enzyme in aldosterone biosynthesis, its inhibition constitutes a promising treatment for these diseases. Via a structure-based approach, a series of pyridyl substituted 3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-ones were designed as inhibitors of aldosterone synthase. Six compounds (5j, 5l, 5m 5w, 5x and 5y) distinguished themselves with potent inhibition (IC50 < 100 nmol/L) and high selectivity over homogenous 11β-hydroxylase. As the most promising compound, 5x exhibited an IC50 of 12 nmol/L and an excellent selectivity factor (SF) of 157, which are both superior to those of the reference fadrazole (IC50=21 nmol/L, SF=7). Importantly, 5x showed no inhibition against steroidogenic CYP17, CYP19 and a panel of hepatic CYP enzymes indicating an outstanding safety profile. As it manifested satisfactory pharmacokinetic properties in rats, compound 5x was considered as a drug candidate for further development.
Exorbitant aldosterone is closely associated with various severe diseases, including congestive heart failure and chronic kidney disease. As aldosterone synthase is the pivotal enzyme in aldosterone biosynthesis, its inhibition constitutes a promising treatment for these diseases. Via a structure-based approach, a series of pyridyl substituted 3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-ones were designed as inhibitors of aldosterone synthase. Six compounds (5j, 5l, 5m 5w, 5x and 5y) distinguished themselves with potent inhibition (IC50 < 100 nmol/L) and high selectivity over homogenous 11β-hydroxylase. As the most promising compound, 5x exhibited an IC50 of 12 nmol/L and an excellent selectivity factor (SF) of 157, which are both superior to those of the reference fadrazole (IC50=21 nmol/L, SF=7). Importantly, 5x showed no inhibition against steroidogenic CYP17, CYP19 and a panel of hepatic CYP enzymes indicating an outstanding safety profile. As it manifested satisfactory pharmacokinetic properties in rats, compound 5x was considered as a drug candidate for further development.
2021, 32(7): 2333-2337
doi: 10.1016/j.cclet.2020.11.074
Abstract:
In this paper, the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO2 material. The ammonia reduction leaching mechanism of LiCoO2 material in the ammonia-sodium sulfite-ammonium chloride system was elucidated. Compared with untreated LiCoO2 material, the leaching equilibrium time of LiCoO2 after ball-milled for 5 h was reduced from 48 h to 4 h, and the leaching efficiency of lithium and cobalt was improved from 69.86% and 70.80% to 89.86% and 98.22%, respectively. Importantly, the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model, indicating that the reaction was controlled by the chemical reaction.
In this paper, the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO2 material. The ammonia reduction leaching mechanism of LiCoO2 material in the ammonia-sodium sulfite-ammonium chloride system was elucidated. Compared with untreated LiCoO2 material, the leaching equilibrium time of LiCoO2 after ball-milled for 5 h was reduced from 48 h to 4 h, and the leaching efficiency of lithium and cobalt was improved from 69.86% and 70.80% to 89.86% and 98.22%, respectively. Importantly, the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model, indicating that the reaction was controlled by the chemical reaction.
2021, 32(7): 2338-2341
doi: 10.1016/j.cclet.2020.10.027
Abstract:
Hyperterpenoid A (1) and B (2), two pairs of enantiomers, with an unprecedented 6/6/4/6/6 polycyclic skeleton, along with one known compoud hypermonone A (3) were isolated from Hypericum beanii. The racemate (±)-1 and (±)-2 were successfully separated into the two optically pure enantiomers (ee ≥ 99%) using a preparative HPLC system. Their absolute configurations were elucidated by extensive spectroscopic analyses and single-crystal X-ray diffraction method. The related plausible biogenetic pathways were presented. Compound 1-3 showed significant neuroprotective activity and potential anti-inflammatory activity. The result that (+)-2 and (-)-2 presented different anti-inflammatory properties, may lead us to new discovery of structure activity relationship between racemates, enantiomers, and diastereomers, as well as further research regarding the binding of drugs to target proteins.
Hyperterpenoid A (1) and B (2), two pairs of enantiomers, with an unprecedented 6/6/4/6/6 polycyclic skeleton, along with one known compoud hypermonone A (3) were isolated from Hypericum beanii. The racemate (±)-1 and (±)-2 were successfully separated into the two optically pure enantiomers (ee ≥ 99%) using a preparative HPLC system. Their absolute configurations were elucidated by extensive spectroscopic analyses and single-crystal X-ray diffraction method. The related plausible biogenetic pathways were presented. Compound 1-3 showed significant neuroprotective activity and potential anti-inflammatory activity. The result that (+)-2 and (-)-2 presented different anti-inflammatory properties, may lead us to new discovery of structure activity relationship between racemates, enantiomers, and diastereomers, as well as further research regarding the binding of drugs to target proteins.
2021, 32(7): 2342-2346
doi: 10.1016/j.cclet.2020.12.014
Abstract:
Molybdenum disulfide (MoS2) has excellent trapping ability for lead ions whereas its micro-/nanoscale size has greatly impeded its practical applications in the flow-through systems. Herein, a millimeter-sized nanocomposite MoS2−001 was synthesized for Pb2+ removal by loading MoS2 nanosheets into a polystyrene cation exchanger D-001 by a facile hydrothermal method. The proposed structure and adsorption mechanism of MoS2−001 was confirmed by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. The nanocomposite showed outstanding adsorption capacity and rapid adsorption kinetic for Pb2+ removal, and the adsorption behavior followed the Langmuir adsorption model and pseudo-first-model kinetic model. Pb2+ uptake by MoS2−001 still maintains a high level even in the presence of extremely highly competitive ions (Ca(Ⅱ) and Mg(Ⅱ)), suggesting its high selectivity for Pb2+ adsorption. Besides, the fixed-bed column experiments further certified that MoS2−001 is of great potential for Pb2+ removal from the wastewater in practical engineering applications. Even more gratifying is that the exhausted MoS2−001 can be regenerated by NaCl-EDTANa2 solution without any significant adsorption capacity loss. Consequently, all the results indicated that MoS2−001 is a promising candidate adsorbent for lead-containing wastewater treatment.
Molybdenum disulfide (MoS2) has excellent trapping ability for lead ions whereas its micro-/nanoscale size has greatly impeded its practical applications in the flow-through systems. Herein, a millimeter-sized nanocomposite MoS2−001 was synthesized for Pb2+ removal by loading MoS2 nanosheets into a polystyrene cation exchanger D-001 by a facile hydrothermal method. The proposed structure and adsorption mechanism of MoS2−001 was confirmed by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. The nanocomposite showed outstanding adsorption capacity and rapid adsorption kinetic for Pb2+ removal, and the adsorption behavior followed the Langmuir adsorption model and pseudo-first-model kinetic model. Pb2+ uptake by MoS2−001 still maintains a high level even in the presence of extremely highly competitive ions (Ca(Ⅱ) and Mg(Ⅱ)), suggesting its high selectivity for Pb2+ adsorption. Besides, the fixed-bed column experiments further certified that MoS2−001 is of great potential for Pb2+ removal from the wastewater in practical engineering applications. Even more gratifying is that the exhausted MoS2−001 can be regenerated by NaCl-EDTANa2 solution without any significant adsorption capacity loss. Consequently, all the results indicated that MoS2−001 is a promising candidate adsorbent for lead-containing wastewater treatment.
