Atomically dispersed metal sites(ADMSs)play key roles in electrochemical energy conversion.The covalent organic frameworks(COFs)enable the precise control of the chemical compositions and structures at the molecular l...Atomically dispersed metal sites(ADMSs)play key roles in electrochemical energy conversion.The covalent organic frameworks(COFs)enable the precise control of the chemical compositions and structures at the molecular level,making them ideal substrates for supporting ADMSs.In this review,we systematically summarize the recent progress on the design and synthesis of ADMSs in COFs,including embedding molecular catalysts into COFs,immobilizing ADMSs on heteroatom-containing COFs,and preparing COF-derived carbon materials through pyrolysis.The electrocatalytic performance of the resulting catalysts is presented for various electrochemical reactions,involving oxygen reduction reaction(ORR),carbon dioxide reduction reaction(CO_(2)RR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and nitrogen reduction reaction(NRR).The modulation strategies of AMDSs in COFs for enhanced activity,selectivity,and stability are highlighted,together with a perspective of the current challenges and the future opportunities in this field.展开更多
MXenes,as an emerging 2D material,are expected to exert a great influence on future energy storage and conversion technologies.In this review,we systematically summarize recent advances in MXene-based materials in ele...MXenes,as an emerging 2D material,are expected to exert a great influence on future energy storage and conversion technologies.In this review,we systematically summarize recent advances in MXene-based materials in electrocatalysis,particularly in the hydrogen evolution,oxygen evolution,oxygen reduction,nitrogen reduction,and CO2 reduction reactions.Crucial factors influencing the properties of these materials,such as functional groups,conductivity,and interface,are discussed,and challenges to the future development of MXene-based electrocatalysts are presented.展开更多
As one of the most common cathode materials for aqueous zinc-ion batteries(AZIBs),manganese oxides have the advantages of abundant reserves,low cost,and low toxicity.However,the electrochemical mechanism at the cathod...As one of the most common cathode materials for aqueous zinc-ion batteries(AZIBs),manganese oxides have the advantages of abundant reserves,low cost,and low toxicity.However,the electrochemical mechanism at the cathode of aqueous zinc-manganese batteries(AZMBs) is complicated due to different electrode materials,electrolytes and working conditions.These complicated mechanisms severely limit the research progress of AZMBs system and the design of cells with better performance.Hence,the mechanism of AZMBs currently recognized by most researchers according to the classification of the main ions involved in the faradaic reaction is introduced in the review.Then a series of reasons that affect the electrochemical behavior of the battery are summarized.Finally,the failure mechanisms of AZMBs over prolonged cycling are discussed,and the current insufficient research areas of the system are explained,along with the direction of further research being prospected.展开更多
High-energy-density lithium-sulfur batteries has attracted substantial attention as competitive candidates for large-scale energy storage technologies.Still,the adverse“shuttle effect”and sluggish sulfur conversion ...High-energy-density lithium-sulfur batteries has attracted substantial attention as competitive candidates for large-scale energy storage technologies.Still,the adverse“shuttle effect”and sluggish sulfur conversion reaction kinetics immensely obstruct their commercial viability.Herein,a two-dimensional metallic 1T phase WS_(2)(1T-WS_(2))nanosheets modified functional separator is developed to improve the electrochemical performance.Meanwhile,the semiconducting bulk-WS_(2) crystals,and 2H phase WS_(2)(2H-WS_(2))nanosheets with more basal-plane Svacancy defects are also prepared to probe the contributions of the crystal structure(phase),S-vacancy defects,and edges to the Li–S batteries performance experimentally and theoretically.In merits of the synergistic effect of high ion and electron conductivity,enhanced binding ability to lithium polysulfides(LiPSs),and sufficient electrocatalytic active sites,the 1T-WS_(2) shows highly efficient electrocatalysis of LiPSs conversion and further improves Li–S battery performance.As expected,thus-fabricated cells with 1T-WS_(2) nanosheets present superior cycle stability that maintain capacity decline of 0.039%per cycle after 1000 cycles at 1.0 C.The strategy presented here offers a viable approach to reveal the critical factors for LiPSs catalytic conversion,which is beneficial to developing advanced Li–S batteries with enhanced properties.展开更多
Graphene has been successfully modified with palladium nanoparticles in a facile manner by reducing palladium acetate [Pd(OAc)2] in the present of sodium dodecyl sulfate (SDS), which is used as both surfactant and the...Graphene has been successfully modified with palladium nanoparticles in a facile manner by reducing palladium acetate [Pd(OAc)2] in the present of sodium dodecyl sulfate (SDS), which is used as both surfactant and the reducing agent. The palladium nanoparticle-graphene hybrids (Pd-graphene hybrids) are characterized by high- resolution transmission electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. We demonstrate that the Pd-graphene hybrids can act as an efficient catalyst for the Suzuki reaction under aqueous and aerobic conditions, with the reaction reaching completion in as little as 5 min. The influence of the preparation conditions on the catalytic activities of the hybrids is also investigated.展开更多
Krotzkopf verkehrt(kkv)is a key enzyme that catalyzes the synthesis of chitin,an important component of the Drosophila epidermis,trachea,and other tissues.Here,we report the use of comprehensive RNA interference(RNAi)...Krotzkopf verkehrt(kkv)is a key enzyme that catalyzes the synthesis of chitin,an important component of the Drosophila epidermis,trachea,and other tissues.Here,we report the use of comprehensive RNA interference(RNAi)analyses to search for kkv transcriptional regulators.A cell-based RNAi screen identified 537 candidate kkv regulators on a genome-wide scale.Subsequent use of transgenic Drosophila lines expressing RNAi constructs enabled in vivo validation,and we identified six genes as potential kkv transcriptional regulators.Weakening of the kkvDsRed signal,an in vivo reporter indicating kkv promoter activity,was observed when the expression of Akirin,NFAT,48 related 3(Fer3),or Autophagy-related 101(Atg101)was knocked down in Drosophila at the 3rd-instar larval stage;whereas we observed disoriented taenidial folds on larval tracheae when Lines(lin)or Autophagy-related 3 (Atg3)was knocked down in the tracheae.Fer3,in particular,has been shown to be an important factor in the activation of kkv transcription via specific binding with the kkv promoter.The genes involved in the chitin synthesis pathway were widely affected by the downregulation of Fer3.Furthermore,Atg101,Atg3,Akirin,Lin,NFAT,Pnr,and Abd-A showed that the potential complex mechanism of kkv transcription is regulated by an interaction network with bithorax complex components.Our study revealed the hitherto unappreciated diversity of modulators impinging on kkv transcription and opens new avenues in the study of kkv regulation and chitin biosynthesis.展开更多
Two-dimensional(2 D) hierarchical Mn_(2)O_(3)@graphene composite is synthesized by a one-step solid-phase reaction. The nanosheets of Mn_(2)O_(3) are vertically grown on few-layered graphene, constructing a unique2 D ...Two-dimensional(2 D) hierarchical Mn_(2)O_(3)@graphene composite is synthesized by a one-step solid-phase reaction. The nanosheets of Mn_(2)O_(3) are vertically grown on few-layered graphene, constructing a unique2 D hierarchical structure. As an anode material for lithium-ion batteries(LIBs), this hierarchical composite displays excellent electrochemical performances, showing an extraordinary reversible discharge capacity of 2125.9 mA hg^(–1). Moreover, a record high reversible capacity of 1746.8 mA hg^(–1) is maintained after 100 cycles at a current density of 100 mA g^(–1), which retains 82.2 % of the initial capacity. Such an outstanding performance could be attributed to its novel structure and the synergistic effects between the Mn_(2)O_(3) and graphene.展开更多
基金supported by the National Natural Science Funds(No.21878226)Innovative Research Group Project of the National Natural Science Foundation of China(No.22121004)。
文摘Atomically dispersed metal sites(ADMSs)play key roles in electrochemical energy conversion.The covalent organic frameworks(COFs)enable the precise control of the chemical compositions and structures at the molecular level,making them ideal substrates for supporting ADMSs.In this review,we systematically summarize the recent progress on the design and synthesis of ADMSs in COFs,including embedding molecular catalysts into COFs,immobilizing ADMSs on heteroatom-containing COFs,and preparing COF-derived carbon materials through pyrolysis.The electrocatalytic performance of the resulting catalysts is presented for various electrochemical reactions,involving oxygen reduction reaction(ORR),carbon dioxide reduction reaction(CO_(2)RR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and nitrogen reduction reaction(NRR).The modulation strategies of AMDSs in COFs for enhanced activity,selectivity,and stability are highlighted,together with a perspective of the current challenges and the future opportunities in this field.
文摘MXenes,as an emerging 2D material,are expected to exert a great influence on future energy storage and conversion technologies.In this review,we systematically summarize recent advances in MXene-based materials in electrocatalysis,particularly in the hydrogen evolution,oxygen evolution,oxygen reduction,nitrogen reduction,and CO2 reduction reactions.Crucial factors influencing the properties of these materials,such as functional groups,conductivity,and interface,are discussed,and challenges to the future development of MXene-based electrocatalysts are presented.
基金supported by the National Natural Science Foundation of China (No. 21878226, No. U20A20153)the Chemistry and Chemical Engineering Guangdong Laboratory (Grant No. 1912011)。
文摘As one of the most common cathode materials for aqueous zinc-ion batteries(AZIBs),manganese oxides have the advantages of abundant reserves,low cost,and low toxicity.However,the electrochemical mechanism at the cathode of aqueous zinc-manganese batteries(AZMBs) is complicated due to different electrode materials,electrolytes and working conditions.These complicated mechanisms severely limit the research progress of AZMBs system and the design of cells with better performance.Hence,the mechanism of AZMBs currently recognized by most researchers according to the classification of the main ions involved in the faradaic reaction is introduced in the review.Then a series of reasons that affect the electrochemical behavior of the battery are summarized.Finally,the failure mechanisms of AZMBs over prolonged cycling are discussed,and the current insufficient research areas of the system are explained,along with the direction of further research being prospected.
基金supported by the National Natural Science Funds,China(No.21676198)the Program of Introducing Talents of Discipline to Universities,China(No.B06006)。
文摘High-energy-density lithium-sulfur batteries has attracted substantial attention as competitive candidates for large-scale energy storage technologies.Still,the adverse“shuttle effect”and sluggish sulfur conversion reaction kinetics immensely obstruct their commercial viability.Herein,a two-dimensional metallic 1T phase WS_(2)(1T-WS_(2))nanosheets modified functional separator is developed to improve the electrochemical performance.Meanwhile,the semiconducting bulk-WS_(2) crystals,and 2H phase WS_(2)(2H-WS_(2))nanosheets with more basal-plane Svacancy defects are also prepared to probe the contributions of the crystal structure(phase),S-vacancy defects,and edges to the Li–S batteries performance experimentally and theoretically.In merits of the synergistic effect of high ion and electron conductivity,enhanced binding ability to lithium polysulfides(LiPSs),and sufficient electrocatalytic active sites,the 1T-WS_(2) shows highly efficient electrocatalysis of LiPSs conversion and further improves Li–S battery performance.As expected,thus-fabricated cells with 1T-WS_(2) nanosheets present superior cycle stability that maintain capacity decline of 0.039%per cycle after 1000 cycles at 1.0 C.The strategy presented here offers a viable approach to reveal the critical factors for LiPSs catalytic conversion,which is beneficial to developing advanced Li–S batteries with enhanced properties.
基金The authors would like to acknowledge the support of this work by the National Natural Science Foundation of China(20776095)and the Programme of Introducing Talents of Discipline to Universities(No.B06006).
文摘Graphene has been successfully modified with palladium nanoparticles in a facile manner by reducing palladium acetate [Pd(OAc)2] in the present of sodium dodecyl sulfate (SDS), which is used as both surfactant and the reducing agent. The palladium nanoparticle-graphene hybrids (Pd-graphene hybrids) are characterized by high- resolution transmission electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. We demonstrate that the Pd-graphene hybrids can act as an efficient catalyst for the Suzuki reaction under aqueous and aerobic conditions, with the reaction reaching completion in as little as 5 min. The influence of the preparation conditions on the catalytic activities of the hybrids is also investigated.
基金This work was supported by the National Natural Science Foundation for the Youth of China(31301716).
文摘Krotzkopf verkehrt(kkv)is a key enzyme that catalyzes the synthesis of chitin,an important component of the Drosophila epidermis,trachea,and other tissues.Here,we report the use of comprehensive RNA interference(RNAi)analyses to search for kkv transcriptional regulators.A cell-based RNAi screen identified 537 candidate kkv regulators on a genome-wide scale.Subsequent use of transgenic Drosophila lines expressing RNAi constructs enabled in vivo validation,and we identified six genes as potential kkv transcriptional regulators.Weakening of the kkvDsRed signal,an in vivo reporter indicating kkv promoter activity,was observed when the expression of Akirin,NFAT,48 related 3(Fer3),or Autophagy-related 101(Atg101)was knocked down in Drosophila at the 3rd-instar larval stage;whereas we observed disoriented taenidial folds on larval tracheae when Lines(lin)or Autophagy-related 3 (Atg3)was knocked down in the tracheae.Fer3,in particular,has been shown to be an important factor in the activation of kkv transcription via specific binding with the kkv promoter.The genes involved in the chitin synthesis pathway were widely affected by the downregulation of Fer3.Furthermore,Atg101,Atg3,Akirin,Lin,NFAT,Pnr,and Abd-A showed that the potential complex mechanism of kkv transcription is regulated by an interaction network with bithorax complex components.Our study revealed the hitherto unappreciated diversity of modulators impinging on kkv transcription and opens new avenues in the study of kkv regulation and chitin biosynthesis.
基金financially supported by the National Natural Science Foundation of China(No.21878226)。
文摘Two-dimensional(2 D) hierarchical Mn_(2)O_(3)@graphene composite is synthesized by a one-step solid-phase reaction. The nanosheets of Mn_(2)O_(3) are vertically grown on few-layered graphene, constructing a unique2 D hierarchical structure. As an anode material for lithium-ion batteries(LIBs), this hierarchical composite displays excellent electrochemical performances, showing an extraordinary reversible discharge capacity of 2125.9 mA hg^(–1). Moreover, a record high reversible capacity of 1746.8 mA hg^(–1) is maintained after 100 cycles at a current density of 100 mA g^(–1), which retains 82.2 % of the initial capacity. Such an outstanding performance could be attributed to its novel structure and the synergistic effects between the Mn_(2)O_(3) and graphene.
