Sisyphus effects in hydrogen electrochemistry on metal silicides enabled by silicene subunit edge

作     者：Zechao Zhuang Yong Li Jiazhao Huang Zilan Li Kangning Zhao Yunlong Zhao Lin Xu Liang Zhou Lyudmila V. Moskaleva Liqiang Mai 

作者机构：State Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingInternational School of Materials Science and EngineeringWuhan University of Technology Institute of Applied and Physical Chemistry and Center for Environmental Research and Sustainable TechnologyUniversity of Bremen Advanced Technology InstituteUniversity of Surrey Department of ChemistryUniversity of the Free State 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2019年第64卷第9期

页      面：617-624页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：supported by the National Key Research and Development Program of China (2016YFA0202603) the National Basic Research Program of China (2013CB934103) the Programme of Introducing Talents of Discipline to Universities (B17034) the National Natural Science Foundation of China (51521001, 51832004) the National Natural Science Fund for Distinguished Young Scholars (51425204) the Fundamental Research Funds for the Central Universities (WUT: 2017III008, 2017III009) 

主　　题：Sisyphus effect Electrochemistry Metal silicides Silicene subunit Hydrogen evolution reaction 

摘      要：Nonmetal elements strictly govern the electrochemical performance of molybdenum ***,the exact role played by nonmetals during electrocatalysis remains largely *** intermetallic MoSi_2comprising silicene subunits,we present an unprecedented hydrogen evolution reaction(HER)behavior in aqueous alkaline *** continuous operation,the HER activity of MoSi_2shows a more than one order of magnitude improvement in current density from 1.1 to 21.5 mA cm^(à2)at 0.4 V ***,this activation behavior is highly reversible,such that voltage withdrawal leads to catalyst inactivation but another operation causes ***,the system shows dynamics strikingly analogous to the legendary Sisyphus’labor,which drops and recovers in a stepwise manner repeatedly,but never succeeds in reaching the top of the *** WSi_2behaves almost the same as MoSi_2,whereas other metal silicides with silicyne subunits,including CrSi_2and TaSi_2,do not exhibit any anomalous behavior.A thin amorphous shell of MoSi_2is observed after reaction,within which the Si remains partially oxidized while the oxidation state of Mo is basically ***-principles calculations further reveal that the adsorption of hydroxide ions on silicene subunit edges and the subsequent Si vacancy formation in MoSi_2jointly lead to the anomalous HER kinetics of the adjacent Mo active *** work demonstrates that the role of nonmetal varies dramatically with the electronic and crystallographic structures of silicides and that silicene structural subunit may serve as a promoter for boosting HER in alkaline media.