Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optim...Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise.Here,we have designed a threedimensional(3D)hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a onepot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process.The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07°and an underwater bubble contact angle of 155.7°,thus facilitating an escape of bubbles from the electrodes.Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN,which can promote the adsorption/desorption of reactants and intermediates.The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at10 mA cm^(-2).The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm^(-2),which is approximately 209 mV lower than water electrolysis.展开更多
Two-dimensional layered transition metal carbides(MXenes),have huge potential advantage for applications in hydrogen evolution reaction(HER).However,the hindered hydrogen evolution at large current densities and the i...Two-dimensional layered transition metal carbides(MXenes),have huge potential advantage for applications in hydrogen evolution reaction(HER).However,the hindered hydrogen evolution at large current densities and the instability of MXenes during HER remains major challenges.Herein,we report the MoS_(2)/Mo_(2)CT_(x) nanoarray with aerophobic structure via molten salt synthesis.In situ vertical distribution of MoS_(2)nanoarray on the surface of Mo_(2)CT_(x) accelerates hydrogen gas release from the electrode,exhibiting significantly enhanced catalytic activity and stability to bare MoS_(2)and Mo_(2)CT_(x).The MoS_(2)/Mo_(2)CT_(x) nanoarray possesses excellent stability at100 mA/cm^(2)for 100 h with only 3%overpotential increase.Our work provides guidance for developing high-stability MXene-based catalysts by virtue of in situ bonding between nanoarray and MXene.展开更多
Electrochemical oxygen reduction reaction(ORR)is crucial for fuel cells and metal-air batteries,while the oxygen consumption dynamics study during ORR,which affects the ORR efficiency,is not as concerned as catalysts ...Electrochemical oxygen reduction reaction(ORR)is crucial for fuel cells and metal-air batteries,while the oxygen consumption dynamics study during ORR,which affects the ORR efficiency,is not as concerned as catalysts design does.Herein the consumption behavior of an individual oxygen bubble on Pt foils with different wettabilities during ORR was tracked by a real-time approach to reveal whether the surface wettability of electrode can influence the consumption dynamics and determine the reaction reactive zones of oxygen bubble consumption.The oxygen bubble underwent a "constant contact angle"dominant consumption model on aerophobic Pt foil,while an initial "constant radius"and the subsequent"constant contact angle"oxygen consumption models were observed on aero philic Pt foil.Results here demonstrated that the current was proportional to the bottom contact area,rather than the three-phase contact line of the bubbles according to the fitting curves between individual bubble current and the consumption behavior parameters.This study highlights the important role of the gas-solid interface in influencing the efficiency of gas consumption electrochemical reactions,which shall benefit the understanding of reaction kinetics and the rational design of electrocatalysts.展开更多
基金financially supported by the National Key R&D Program of China(2022YFA1503003)the National Natural Science Foundation of China(91961111,22271081)+3 种基金the Natural Science Foundation of Heilongjiang Province(ZD2021B003)the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(UNPYSCT-2020004)The Basic Research Fund of Heilongjiang University in Heilongjiang Province(2021-KYYWF-0039)the Heilongjiang University Excellent Youth Foundation。
文摘Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise.Here,we have designed a threedimensional(3D)hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a onepot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process.The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07°and an underwater bubble contact angle of 155.7°,thus facilitating an escape of bubbles from the electrodes.Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN,which can promote the adsorption/desorption of reactants and intermediates.The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at10 mA cm^(-2).The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm^(-2),which is approximately 209 mV lower than water electrolysis.
基金supported by the National Science Fund for Distinguished Young Scholars(No.21925603)the National Natural Science Foundation of China(No.22176190)the Ningbo Toptalent Team Program(No.2018A610005).
文摘Two-dimensional layered transition metal carbides(MXenes),have huge potential advantage for applications in hydrogen evolution reaction(HER).However,the hindered hydrogen evolution at large current densities and the instability of MXenes during HER remains major challenges.Herein,we report the MoS_(2)/Mo_(2)CT_(x) nanoarray with aerophobic structure via molten salt synthesis.In situ vertical distribution of MoS_(2)nanoarray on the surface of Mo_(2)CT_(x) accelerates hydrogen gas release from the electrode,exhibiting significantly enhanced catalytic activity and stability to bare MoS_(2)and Mo_(2)CT_(x).The MoS_(2)/Mo_(2)CT_(x) nanoarray possesses excellent stability at100 mA/cm^(2)for 100 h with only 3%overpotential increase.Our work provides guidance for developing high-stability MXene-based catalysts by virtue of in situ bonding between nanoarray and MXene.
基金the National Natural Science Foundation of China(Nos.21675007,21676015,21520102002,91622116)the National Key Research and Development Project of China(Nos.2018YFB1502401,2018YFA0702002),the Royal Society and the Newton Fund Through the Newton Advanced Fellowship Award(No.NAF/R1/191294)+2 种基金the Program for Changjiang Scholars and Innovation Research Team in the University,China(No.IRT1205)Fundamental Research Funds for the Central Universities of Chinathe Long-term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of China。
文摘Electrochemical oxygen reduction reaction(ORR)is crucial for fuel cells and metal-air batteries,while the oxygen consumption dynamics study during ORR,which affects the ORR efficiency,is not as concerned as catalysts design does.Herein the consumption behavior of an individual oxygen bubble on Pt foils with different wettabilities during ORR was tracked by a real-time approach to reveal whether the surface wettability of electrode can influence the consumption dynamics and determine the reaction reactive zones of oxygen bubble consumption.The oxygen bubble underwent a "constant contact angle"dominant consumption model on aerophobic Pt foil,while an initial "constant radius"and the subsequent"constant contact angle"oxygen consumption models were observed on aero philic Pt foil.Results here demonstrated that the current was proportional to the bottom contact area,rather than the three-phase contact line of the bubbles according to the fitting curves between individual bubble current and the consumption behavior parameters.This study highlights the important role of the gas-solid interface in influencing the efficiency of gas consumption electrochemical reactions,which shall benefit the understanding of reaction kinetics and the rational design of electrocatalysts.