MXene is a variety of new two-dimensional(2D)materials with early transition metal carbides,nitrides,and carbonitrides.Quantum chemical studies have been carried out on the geometries,electronic structures,stability a...MXene is a variety of new two-dimensional(2D)materials with early transition metal carbides,nitrides,and carbonitrides.Quantum chemical studies have been carried out on the geometries,electronic structures,stability and catalytic properties of a non-noble metal single-atom catalyst(SAC)with single Co atom anchored on MXene materials of Mo_(2)CS_(2).The Co adatom anchored on top of the Mo atom of this MXene is found to be rather stable,and this SAC is appropriate for CO oxidation.The charge transfers from the surface to the adsorbed CO and O2 play a significant role in the activation of these molecules on Co_(1)/Mo_(2)CS_(2).With this catalyst,the Eley-Rideal(ER),Langmuir-Hinshelwood(LH),and Termolecular Eley-Rideal(TER)mechanisms are explored for CO oxidation.We find that,while all the three mechanisms are feasible at low temperature,Co_(1)/Mo_(2)CS_(2) possesses higher catalytic activity for CO oxidation through the TER mechanism that features an intriguing OC(OO)CO intermediate(IM)adsorbed on Co single atom.The calculated activation energy barriers of the rate-limiting step are 0.67 eV(TER),0.78 eV(LH)and 0.88 eV(ER),respectively.The present study illustrates that it is promising to develop and design low-cost,non-noble metal SACs using MXene types of 2D materials.展开更多
Electrochemical CO2 reduction(ECR)represents a promising strategy for utilizing CO2,an industrial waste,as an abundant and cheap carbon source for organic synthesis as well as storing intermittent renewable electricit...Electrochemical CO2 reduction(ECR)represents a promising strategy for utilizing CO2,an industrial waste,as an abundant and cheap carbon source for organic synthesis as well as storing intermittent renewable electricity from renewable sources.Efficient electrocatalysts allowing CO2 to be reduced selectively and actively are crucial since the ECR is a complex and sluggish process producing a variety of products.Metal-organic frameworks(MOFs)and covalentorganic frameworks(COFs)have emerged as versatile materials applicable in many fields due to their unique properties including high surface areas and tunable pore channels.Besides,the emerging reticular chemistry makes tuning their features on the atomic/molecular levels possible,thereby lending credence to the prospect of their utilizations.Herein,an overview of recent progress in employing framework material-based catalysts,including MOFs,COFs and their derivatives,for ECR is provided.The pertinent challenges,future trends,and opportunities associated with those systems are also discussed.展开更多
Nanocomposites composed of one-dimensional（1D） CdS nanowires（NWs） and 1 T-MoS2 nanosheets have been fabricated through a two-step solvothermal process. 5 mol% of MoS2 loading results in the best optical properties...Nanocomposites composed of one-dimensional（1D） CdS nanowires（NWs） and 1 T-MoS2 nanosheets have been fabricated through a two-step solvothermal process. 5 mol% of MoS2 loading results in the best optical properties,photoelectrochemical（PEC） as well as photocatalytic activities for hydrogen evolution reaction（HER）. Compared with pure CdS NWs, the optimized nanocomposite shows 5.5 times enhancement in photocurrent and 86.3 times increase for HER in the presence of glucose and lactic acid as hole scavengers.The enhanced PEC and HER activities are attributed to the intimate contact between MoS2 and CdS that efficiently enhances charge carrier separation. In addition, ultrafast transient absorption（TA） measurements have been used to probe the charge carrier dynamics and gain deeper insight into the mechanism behind the enhanced PEC and photocatalytic performance.展开更多
Sulfur(S)-doped graphene sheets were prepared by a facile electrochemical method, which effectively combined exfoliation of graphite and in situ S doping of graphene together. The metal-free S-doped graphene sheets ex...Sulfur(S)-doped graphene sheets were prepared by a facile electrochemical method, which effectively combined exfoliation of graphite and in situ S doping of graphene together. The metal-free S-doped graphene sheets exhibit high electrocatalytic activity, long-term stability, and excellent tolerance to cross-over effects of methanol in alkaline media for the oxygen reduction reaction(ORR), indicating that these S-doped graphene sheets possess great potential for a substitute for Pt-based catalysts in fuel cells.展开更多
基金the National Natural Science Foundation of China(21590792,91426302,and 21433005)Guangdong Provincial Key Laboratory of Catalysis(2020B121201002)+1 种基金the National Science Basic Research Program of Shaanxi Province(2019JM-226)the financial and technical support from the Research Center for Advanced Materials Science(RCAMS)at King Khalid University through the Grant(RCAMS/KKU/014-20)。
文摘MXene is a variety of new two-dimensional(2D)materials with early transition metal carbides,nitrides,and carbonitrides.Quantum chemical studies have been carried out on the geometries,electronic structures,stability and catalytic properties of a non-noble metal single-atom catalyst(SAC)with single Co atom anchored on MXene materials of Mo_(2)CS_(2).The Co adatom anchored on top of the Mo atom of this MXene is found to be rather stable,and this SAC is appropriate for CO oxidation.The charge transfers from the surface to the adsorbed CO and O2 play a significant role in the activation of these molecules on Co_(1)/Mo_(2)CS_(2).With this catalyst,the Eley-Rideal(ER),Langmuir-Hinshelwood(LH),and Termolecular Eley-Rideal(TER)mechanisms are explored for CO oxidation.We find that,while all the three mechanisms are feasible at low temperature,Co_(1)/Mo_(2)CS_(2) possesses higher catalytic activity for CO oxidation through the TER mechanism that features an intriguing OC(OO)CO intermediate(IM)adsorbed on Co single atom.The calculated activation energy barriers of the rate-limiting step are 0.67 eV(TER),0.78 eV(LH)and 0.88 eV(ER),respectively.The present study illustrates that it is promising to develop and design low-cost,non-noble metal SACs using MXene types of 2D materials.
基金financially supported by the National Natural Science Foundation of China(21671096 and 11775105)Shenzhen Peacock Plan(KQTD2016022620054656)。
文摘Electrochemical CO2 reduction(ECR)represents a promising strategy for utilizing CO2,an industrial waste,as an abundant and cheap carbon source for organic synthesis as well as storing intermittent renewable electricity from renewable sources.Efficient electrocatalysts allowing CO2 to be reduced selectively and actively are crucial since the ECR is a complex and sluggish process producing a variety of products.Metal-organic frameworks(MOFs)and covalentorganic frameworks(COFs)have emerged as versatile materials applicable in many fields due to their unique properties including high surface areas and tunable pore channels.Besides,the emerging reticular chemistry makes tuning their features on the atomic/molecular levels possible,thereby lending credence to the prospect of their utilizations.Herein,an overview of recent progress in employing framework material-based catalysts,including MOFs,COFs and their derivatives,for ECR is provided.The pertinent challenges,future trends,and opportunities associated with those systems are also discussed.
基金financially supported by the National Natural Science Foundation of China (51402126)support from Delta Dental Health Associates, NASA through MACES (NNX15AQ01A)UCSC Committee on Research Special Research Grant
文摘Nanocomposites composed of one-dimensional（1D） CdS nanowires（NWs） and 1 T-MoS2 nanosheets have been fabricated through a two-step solvothermal process. 5 mol% of MoS2 loading results in the best optical properties,photoelectrochemical（PEC） as well as photocatalytic activities for hydrogen evolution reaction（HER）. Compared with pure CdS NWs, the optimized nanocomposite shows 5.5 times enhancement in photocurrent and 86.3 times increase for HER in the presence of glucose and lactic acid as hole scavengers.The enhanced PEC and HER activities are attributed to the intimate contact between MoS2 and CdS that efficiently enhances charge carrier separation. In addition, ultrafast transient absorption（TA） measurements have been used to probe the charge carrier dynamics and gain deeper insight into the mechanism behind the enhanced PEC and photocatalytic performance.
基金supported by the National Natural Science Foundation of China(21073018)the Major Research Plan of the National Natural Science Foundation of China(21233003)the Fundamental Research Funds for the Central Universities,Key Laboratory of Theoretical and Computational Photochemistry
文摘Sulfur(S)-doped graphene sheets were prepared by a facile electrochemical method, which effectively combined exfoliation of graphite and in situ S doping of graphene together. The metal-free S-doped graphene sheets exhibit high electrocatalytic activity, long-term stability, and excellent tolerance to cross-over effects of methanol in alkaline media for the oxygen reduction reaction(ORR), indicating that these S-doped graphene sheets possess great potential for a substitute for Pt-based catalysts in fuel cells.
