Metastable 1T’MoTe_(2) has attracted much attention as a cost-effective electrocatalyst for hydrogen evolution reaction(HER)in recent years.However,few studies were done over common stable 2 H phase because it often ...Metastable 1T’MoTe_(2) has attracted much attention as a cost-effective electrocatalyst for hydrogen evolution reaction(HER)in recent years.However,few studies were done over common stable 2 H phase because it often exhibits inferior performance.Herein,stable 2H MoTe_(2) with S-doped Te vacancies has been synthesized by one-step telluride conversion of 1T MoS_(2) at 700℃under Ar/H_(2) atmosphere.It is demonstrated that the synergistic effect of S-doping and Te vacancies changes the electronic structures of the catalyst.Density functional theory(DFT)studies show that plentiful electrons accumulate on the surface S atoms in S-doped Te vacancies of 2H MoTe_(2) catalyst,which may be as active sites to promote HER.Moreover,the as-synthesized catalyst can be directly used as working electrode,and realizes current density of 100 mA cm^(-2) at overpotential of 217 mV with Tafel slope of 94 mV dec^(-1).This work stimulates intensive studies on the activation of inert phase of other nanocatalysts towards various reactions.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(21771137)。
文摘Metastable 1T’MoTe_(2) has attracted much attention as a cost-effective electrocatalyst for hydrogen evolution reaction(HER)in recent years.However,few studies were done over common stable 2 H phase because it often exhibits inferior performance.Herein,stable 2H MoTe_(2) with S-doped Te vacancies has been synthesized by one-step telluride conversion of 1T MoS_(2) at 700℃under Ar/H_(2) atmosphere.It is demonstrated that the synergistic effect of S-doping and Te vacancies changes the electronic structures of the catalyst.Density functional theory(DFT)studies show that plentiful electrons accumulate on the surface S atoms in S-doped Te vacancies of 2H MoTe_(2) catalyst,which may be as active sites to promote HER.Moreover,the as-synthesized catalyst can be directly used as working electrode,and realizes current density of 100 mA cm^(-2) at overpotential of 217 mV with Tafel slope of 94 mV dec^(-1).This work stimulates intensive studies on the activation of inert phase of other nanocatalysts towards various reactions.
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.
