The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water.In this paper,we report the synthesis of cobalt-vanadium（Co-V）bimetal-based ca...The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water.In this paper,we report the synthesis of cobalt-vanadium（Co-V）bimetal-based catalysts for the effective water splitting.The Co_2V_2O_7·xH_2O nanoplates containing both Co and V elements were selected as the precursors.After the calcination under NH_3atmosphere,the Co_2VO_4and Co/VN could be obtained just by tuning the calcination temperature.Electrochemical tests indicated that the Co-V bimetal-based materials could be used as active hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）catalyst by regulating their structure.The Co/VN showed good performance for HER with the onset potential of68 mV and can achieve a current density of 10 mA cm^（-2）at an overpotential of 92 m V.Meanwhile,the Co_2VO_4exhibited the obvious OER performance with overpotential of 300 mV to achieve a current density of 10 mA cm^（-2）.When the Co_2VO_4and Co/VN were used as the anode and cathode in a twoelectrode system,respectively,the cell needed a voltage of1.65 V to achieve 10 mA cm^（-2）together with good stability.This work would be indicative to constructing Co-V bimetalbased catalysts for the catalytic application.展开更多
Since Co_(2)VO_(4) possesses a solid spinel structure and a high degree of stability,it has gained interest as a possible anode material for sodium-ion batteries.However,the application of this electrode material is s...Since Co_(2)VO_(4) possesses a solid spinel structure and a high degree of stability,it has gained interest as a possible anode material for sodium-ion batteries.However,the application of this electrode material is still hampered by its poor electrical conductivity and severe volume expansion.Uniform Co_(2)VO_(4) nanoparticles(CVO)were grown on carbon nanotubes(CNTs)by a simple solvothermal method to form string-like conductive networks(CVO/CNTs).The flexible and highly conductive three-dimensional(3D)carbon nano tubes and small-sized CVO NPs can enhance the rapid transport of electrons,thereby enhancing the conductivity of the composite.String-like conductive network structures have a larger specific surface area,enhancing electron/ion transmission by fully contacting the electrolyte.The findings demonstrate the superior Na^(+)storing capability of the CVO/CNTs composite.The battery has a great rate performance(148.2 mAh·g^(-1)at 5 A·g^(-1))and outstanding long-term cycling performance(147.3 mAh·g^(-1)after 1000 cycles at 1A·g^(-1)).In high-rate,long-cycle sodium-ion batteries,CVO/CNTs composites offer a wide range of possible applications.展开更多
基金supported by the Key Program Projects of the National Natural Science Foundation of China (21631004)the National Natural Science Foundation of China (21601055, 21571054 and 21401048)+1 种基金the Natural Science Foundation of Heilongjiang Province (B2017008)Heilongjiang University Excellent Youth Foundation
文摘The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water.In this paper,we report the synthesis of cobalt-vanadium（Co-V）bimetal-based catalysts for the effective water splitting.The Co_2V_2O_7·xH_2O nanoplates containing both Co and V elements were selected as the precursors.After the calcination under NH_3atmosphere,the Co_2VO_4and Co/VN could be obtained just by tuning the calcination temperature.Electrochemical tests indicated that the Co-V bimetal-based materials could be used as active hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）catalyst by regulating their structure.The Co/VN showed good performance for HER with the onset potential of68 mV and can achieve a current density of 10 mA cm^（-2）at an overpotential of 92 m V.Meanwhile,the Co_2VO_4exhibited the obvious OER performance with overpotential of 300 mV to achieve a current density of 10 mA cm^（-2）.When the Co_2VO_4and Co/VN were used as the anode and cathode in a twoelectrode system,respectively,the cell needed a voltage of1.65 V to achieve 10 mA cm^（-2）together with good stability.This work would be indicative to constructing Co-V bimetalbased catalysts for the catalytic application.
基金financially supported by the National Key Research and Development Project (No.2018YFE0124800)the National Nature Science Foundation of China (No.51702157)。
文摘Since Co_(2)VO_(4) possesses a solid spinel structure and a high degree of stability,it has gained interest as a possible anode material for sodium-ion batteries.However,the application of this electrode material is still hampered by its poor electrical conductivity and severe volume expansion.Uniform Co_(2)VO_(4) nanoparticles(CVO)were grown on carbon nanotubes(CNTs)by a simple solvothermal method to form string-like conductive networks(CVO/CNTs).The flexible and highly conductive three-dimensional(3D)carbon nano tubes and small-sized CVO NPs can enhance the rapid transport of electrons,thereby enhancing the conductivity of the composite.String-like conductive network structures have a larger specific surface area,enhancing electron/ion transmission by fully contacting the electrolyte.The findings demonstrate the superior Na^(+)storing capability of the CVO/CNTs composite.The battery has a great rate performance(148.2 mAh·g^(-1)at 5 A·g^(-1))and outstanding long-term cycling performance(147.3 mAh·g^(-1)after 1000 cycles at 1A·g^(-1)).In high-rate,long-cycle sodium-ion batteries,CVO/CNTs composites offer a wide range of possible applications.
