Designing high active,low cost and bifunctional electrocatalysts is urgent for developing clean energy storage and conversion systems.Transition metal selenides exhibit optimal electronic conductivity and tunable phys...Designing high active,low cost and bifunctional electrocatalysts is urgent for developing clean energy storage and conversion systems.Transition metal selenides exhibit optimal electronic conductivity and tunable physicochemical properties,which endow them with potential for efficient electrocatalysts to facilitate the oxygen reduction and oxygen evolution reactions(ORR and OER).Herein,hollow NixCo0.85-xSe nanospheres were synthesized using a facile polyol based solution chemical method.The NixCo0.85-xSe exhibits an onset overpotential of 0.89 V for ORR,and an overpotential of 305 mV to achieve 10 mA cm^-2 for OER.Moreover,the NixCo0.85-xSe based Zn-air battery displays remarkable specific capacity and durability.Such superior catalytic performances can be attributed to the synergistic effect,large specific surface area and enhanced electron transfer rate.This approach provides a new way to design highly efficient bifunctional electrocatalysts for electrochemical energy storage and utilization.展开更多
In this work, we reported the synthesis of twodimensional spinel structure of ultrathin Co2AlO4 nanosheets via dealloying and subsequent annealing processes. Oxygen vacancy defects were further introduced into Co2AlO4...In this work, we reported the synthesis of twodimensional spinel structure of ultrathin Co2AlO4 nanosheets via dealloying and subsequent annealing processes. Oxygen vacancy defects were further introduced into Co2AlO4 nanosheets by a mild solvothermal reduction method, resulting in large electrochemical surface area and high active site densities, making the related Co atoms get electrons, and producing more empty orbitals. The positive charge of Co and Al atoms adjacent to the O vacancies in VO-rich Co2AlO4 reduced significantly, that is, more electrons are concentrated on the Co and Al atoms. Those electrons closed to the Fermi level have a promoting effect during the H2O activation. As a result, the obtained ultrathin Co2AlO4 nanosheets with oxygen vacancies show a low overpotential of 280 m V at the current density of 10 mA cm^-2 and a small Tafel slope of70.98 m V dec^-1. Moreover, it also displays a remarkable stability in alkaline solution, which is superior to most of the reported Co3O4 electrocatalysts. The present work paves a new way to achieve efficient new energetic materials for sustainable community.展开更多
基金supported by the National Natural Science Foundation of China (51804216)a scholarship from the China Scholarship Council (CSC) (201806255078)
文摘Designing high active,low cost and bifunctional electrocatalysts is urgent for developing clean energy storage and conversion systems.Transition metal selenides exhibit optimal electronic conductivity and tunable physicochemical properties,which endow them with potential for efficient electrocatalysts to facilitate the oxygen reduction and oxygen evolution reactions(ORR and OER).Herein,hollow NixCo0.85-xSe nanospheres were synthesized using a facile polyol based solution chemical method.The NixCo0.85-xSe exhibits an onset overpotential of 0.89 V for ORR,and an overpotential of 305 mV to achieve 10 mA cm^-2 for OER.Moreover,the NixCo0.85-xSe based Zn-air battery displays remarkable specific capacity and durability.Such superior catalytic performances can be attributed to the synergistic effect,large specific surface area and enhanced electron transfer rate.This approach provides a new way to design highly efficient bifunctional electrocatalysts for electrochemical energy storage and utilization.
基金the financial support by the National Natural Science Foundation of China (21771137)the Natural Science Foundation of Tianjin City (18JCJQJC47700)+1 种基金111 project (D17003)the Training Project of Innovation Team of Colleges and Universities in Tianjin (TD13-5020)
文摘In this work, we reported the synthesis of twodimensional spinel structure of ultrathin Co2AlO4 nanosheets via dealloying and subsequent annealing processes. Oxygen vacancy defects were further introduced into Co2AlO4 nanosheets by a mild solvothermal reduction method, resulting in large electrochemical surface area and high active site densities, making the related Co atoms get electrons, and producing more empty orbitals. The positive charge of Co and Al atoms adjacent to the O vacancies in VO-rich Co2AlO4 reduced significantly, that is, more electrons are concentrated on the Co and Al atoms. Those electrons closed to the Fermi level have a promoting effect during the H2O activation. As a result, the obtained ultrathin Co2AlO4 nanosheets with oxygen vacancies show a low overpotential of 280 m V at the current density of 10 mA cm^-2 and a small Tafel slope of70.98 m V dec^-1. Moreover, it also displays a remarkable stability in alkaline solution, which is superior to most of the reported Co3O4 electrocatalysts. The present work paves a new way to achieve efficient new energetic materials for sustainable community.
