Elimination Of Interlayer Potential Barriers Of Chromium Sulfide By Self-intercalation For Enhanced Hydrogen Evolution Reaction

Nowadays,energy crisis is one of the major challenges for our society.Therefore,many researchers are committed to develop clean energy to meet the demand of the national life,and hydrogen is an ideal carrier of clean energy.Currently electrocatalytic hydrogen production is the most promising way to generate hydrogen.Thus,it is of great significance to find a suitable electrocatalyst to maximize the efficiency of hydrogen generation.At present,the most stable and active catalysts are noble metals,especially Pt based materials in acidic solution.However,due to the scarcity of Pt resources and its high cost,it is necessary to explore a new material,which needs to be cheaper,abundant,good stability,high activity,and has a smaller overpotential.Transition metal dihalides（TMDs）,such as Mo S₂and WS₂,have attracted much attention due to their excellent optical,electronic and electrochemical properties.Hence,these monolayer and multilayer TMDs are considered to be the most promising catalysts as a substitution of Pt based materials.The van der Waals（vd W）gaps in layered transition metal dichalcogenides（TMDs）with interlayer poor charge transport is considered the bottleneck for higher hydrogen evolution reaction（HER）performance of TMDs.Filling the vd W gap of TMDs materials with intercalants considered as a good way to generate new interesting properties.However,post-synthesis intercalation with foreign atoms may bring extra crystalline imperfections and low yields.In this work,to overcome the interlayer potential barriers of TMDs,Cr S₂-Cr_1/3-Cr S₂is produced by naturally self-intercalating native Cr_1/3atom plane into the vd W layered Cr S₂.The Cr S₂-Cr_1/3-Cr S₂exhibits strong chemical bonds and high electrical conductivity,which can provide excellent HER electrocatalytic performance.Moreover,based on first-principles calculations and experimental verification,the intercalated Cr atoms exhibits a Gibbs free energy of adsorbed hydrogen close to zero and could further improve electrocatalytic HER performance.Our work provides a new view in self-intercalation for electrocatalysis applications.