Metastable molybdenum carbide(α-MoC),as a catalyst and an excellent support for metal catalysts,has been widely used in thermo/electro-catalytic reactions.However,the selective synthesis ofα-MoC remains a great chal...Metastable molybdenum carbide(α-MoC),as a catalyst and an excellent support for metal catalysts,has been widely used in thermo/electro-catalytic reactions.However,the selective synthesis ofα-MoC remains a great challenge.Herein,a simple one-pot synthetic strategy for the selective preparation of metastableα-MoC is proposed by electrochemical co-reduction of CO_(2)and MoO_(3)in a low-temperature eutectic molten carbonate.The synthesizedα-MoC shows a reed flower-like morphology.By controlling the electrolysis time and monitoring the phase and morphology of the obtained products,the growth process ofα-MoC is revealed,where the carbon matrix is deposited first followed by the growth ofα-MoC from the carbon matrix.Moreover,by analyzing the composition of the electrolytic products,the formation mechanism forα-MoC is proposed.In addition,through this one-pot synthetic strategy,S-dopedα-MoC is successfully synthesized.Density functional theory(DFT)calculations reveal that S doping enhanced the HER performance ofα-MoC by facilitating water absorption and dissociation and weakening the bond energy of Mo-H to accelerate H desorption.The present work not only highlights the valuable utilization of CO_(2) but also offers a new perspective on the design and controllable synthesis of metal carbides and their derivatives.展开更多
Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-deri...Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-derived carbon(CDC)encapsulated with porous N-doped carbon(CDC@NC)towards highperformance supercapacitors.Polydopamine(PDA)as nitrogen and carbon sources was simply coated on SiC nanospheres to form SiC@PDA,which was then directly transformed into CDC@NC via a onestep molten salt electro-etching/in-situ doping process.The synthesized CDC@NC with hierarchically porous structure has a high specific surface area of 1191 m^(2) g^(-1).The CDC core and NC shell are typical amorphous carbon and more ordered N-doped carbon,respectively.Benefitting from its unique dual porous structures,the CDC@NC demonstrates high specific capacitances of 255 and 193 F g^(-1) at 0.5 and20 A g^(-1),respectively.The reaction mechanism of the electro-etching/in-situ doping process has also been investigated through experimental characterizations and theoretical density functional theory calculations.It is suggested that the molten salt electro-etching/in-situ doping strategy is promising for the synthesis of active core-shell porous carbon materials with synergistic properties for supercapacitors without the need for additional doping/activation processes.展开更多
基金the financial support from National Natural Science Foundation of China(Nos.22071070,21971077).
文摘Metastable molybdenum carbide(α-MoC),as a catalyst and an excellent support for metal catalysts,has been widely used in thermo/electro-catalytic reactions.However,the selective synthesis ofα-MoC remains a great challenge.Herein,a simple one-pot synthetic strategy for the selective preparation of metastableα-MoC is proposed by electrochemical co-reduction of CO_(2)and MoO_(3)in a low-temperature eutectic molten carbonate.The synthesizedα-MoC shows a reed flower-like morphology.By controlling the electrolysis time and monitoring the phase and morphology of the obtained products,the growth process ofα-MoC is revealed,where the carbon matrix is deposited first followed by the growth ofα-MoC from the carbon matrix.Moreover,by analyzing the composition of the electrolytic products,the formation mechanism forα-MoC is proposed.In addition,through this one-pot synthetic strategy,S-dopedα-MoC is successfully synthesized.Density functional theory(DFT)calculations reveal that S doping enhanced the HER performance ofα-MoC by facilitating water absorption and dissociation and weakening the bond energy of Mo-H to accelerate H desorption.The present work not only highlights the valuable utilization of CO_(2) but also offers a new perspective on the design and controllable synthesis of metal carbides and their derivatives.
基金sponsored by the National Natural Science Foundation of China(5197418151574164)+5 种基金the Iron and Steel Joint Research Found of National Natural Science Foundation and China Baowu Steel Group Corporation Limited(U1860203)the Shanghai Rising-Star Program(19QA1403600)China Postdoctoral Science Foundation(2019M661462)the Shanghai Postdoctoral Excellence Program(2018079)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher learning(TP2019041)the CAS Interdisciplinary Innovation Team and High Performance Computing Center,Shanghai University for financial support。
文摘Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-derived carbon(CDC)encapsulated with porous N-doped carbon(CDC@NC)towards highperformance supercapacitors.Polydopamine(PDA)as nitrogen and carbon sources was simply coated on SiC nanospheres to form SiC@PDA,which was then directly transformed into CDC@NC via a onestep molten salt electro-etching/in-situ doping process.The synthesized CDC@NC with hierarchically porous structure has a high specific surface area of 1191 m^(2) g^(-1).The CDC core and NC shell are typical amorphous carbon and more ordered N-doped carbon,respectively.Benefitting from its unique dual porous structures,the CDC@NC demonstrates high specific capacitances of 255 and 193 F g^(-1) at 0.5 and20 A g^(-1),respectively.The reaction mechanism of the electro-etching/in-situ doping process has also been investigated through experimental characterizations and theoretical density functional theory calculations.It is suggested that the molten salt electro-etching/in-situ doping strategy is promising for the synthesis of active core-shell porous carbon materials with synergistic properties for supercapacitors without the need for additional doping/activation processes.