He Qiaoqiao, Chen Xiaobo, Chen Shiqi, Liu Lu, Zhou Fangwang, Li Xi-Bo, Wang Guangjin
Siyuan Laboratory, Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy Materials, Department of Physics , Jinan University , Guangzhou , Guangdong 510632 , China.
Center for Functional Nanomaterials , Brookhaven National Laboratory , Upton , New York 11973 , United States.
ACS Appl Mater Interfaces. 2019 Jan 23;11(3):2944-2949. doi: 10.1021/acsami.8b17075. Epub 2019 Jan 14.
Density functional theory calculations are carried out to study the hydrogen evolution reaction (HER) at the electrochemical double-layer interface of monolayer 2H phase VS and water. Under typical conditions of HER, the catalyst surface is predicted to have a low hydrogen coverage of about 12%, whereas the aqueous solution side features a high hydronium concentration of about 8.3%. As a result, the HER takes place through the Volmer-Heyrovsky route, with an overall reaction barrier of about 1.0 eV, much larger than that of 1T phase VS. This result demonstrates that 2H phase VS is much less reactive than its 1T phase counterpart, and the 1T-to-2H phase transformation induced by thickness reduction may deteriorate the HER activity of VS.
进行密度泛函理论计算以研究单层2H相VS与水在电化学双层界面处的析氢反应（HER）。在HER的典型条件下，预测催化剂表面的氢覆盖率较低，约为12%，而水溶液一侧的水合氢离子浓度较高，约为8.3%。因此，HER通过Volmer-Heyrovsky途径发生，总反应势垒约为1.0 eV，远大于1T相VS的反应势垒。该结果表明，2H相VS的反应活性远低于其1T相对应物，厚度减小引起的1T相向2H相转变可能会降低VS的HER活性。
