First-Principle Study On The Catalytic Performance Of Two-Dimensional Inorganic Materials Towards Hydrogen Evolution Reaction

Graphene has become a research hotspot in nanomaterial in the past 20 years,duo to its wide range of applications.While graphene has been extensively and deeply studied,other two-dimensional（2D）graphene-like inorganic materials,including transition-metal dichalcogenides（TMDs）,MXene and g-C₃N₄,have also aroused people’s interest and achieved many important achievement.The excellent hydrogen evolution reaction（HER）performance of 2D inorganic graphene-like materials,such as molybdenum disulfide（Mo S₂）and phosphoene,has attracted widespread attention.In our works,we use the density functional theory（DFT）to study the physical chemical properties of different graphene-like materials systems and their applications in electrocatalytic hydrogen evolution reaction（HER）.Firstly,the effect of 2H-Mo S₂ with different sulfur vacancies concentrations on HER was studied.Vacancy-engineering is considered as one of the effective means to improve the catalytic activity by changing the electronic structure.In experiment,there are many methods to create sulfur vacancies in 2H-Mo S₂,exposing the Mo atoms inside.The geometrical and electronic structures of defective 2H-Mo S₂ at different sulfur vacancies concentrations have been studied and used it in HER to investigate its electrocatalytic activity.The calculated results indicated that when the sulfur vacancies concentration less than 12.50%,defective 2H-Mo S₂ can be a great HER electrocatalyst.Secondly,considering the sulfur vacancy defective 2H-Mo S₂（which can be a great HER catalyst）storage environment is under the condition of the atmosphere,so we studied the interaction between the defective 2H-Mo S₂ with different sulfur vacancies concentration and four major air molecules in the atmosphere（nitrogen,oxygen,carbon dioxide and water）,and then studied the defective 2H-Mo S₂ reacted with the air molecules HER activity.The results show that the defective 2H-Mo S₂ reacts easily with oxygen molecules in the air to form oxygen doping structure.Compared with the pristine 2H-Mo S₂,the electrocatalytic activity of oxygen-doping defective 2H-Mo S₂ is greatly improved when used in HER.Finally,the effect of covalent functionalized monolayer black phosphorous（BP）on the HER was studied.The physical chemical properties of BP are superior to graphene in many aspects.However,BP is unstable in atmospheric conditions and is very easy to degrade,and covalent functionalization is an effective means to maintain its structural stability.The geometry,electronic structure and catalytic activity of covalently functionalized BP for HER have been studied.The results pointed that covalent functionalized BP,especially when the coverage of covalent functional groups is 8.33%,has good electrocatalytic activity.