Theoretical Study On Electrocatalysts For Hydrogen Evolution Reaction Based On Two-Dimensional Materials

Nowadays,the energy crisis and environmental pollution problems are becoming increasingly serious.In order to reduce people’s excessive dependence on fossil fuel,exploring clean and renewable energy has become an important task.In recent years,hydrogen,as an energy carrier with the advantages of high energy density and no carbon emission,has been identified as the most promising clean energy to alleviate the increasingly serious pollution problem.Compared with traditional hydrogen production strategies,electrocatalytic water splitting is considered to be an efficient and environmentally friendly method for hydrogen production,which has the characteristics of high catalytic efficiency,high hydrogen production purity,and no greenhouse gas production.In the process of water electrolysis,the hydrogen evolution reaction is an important kinetic process,which largely determines the efficiency of hydrogen production.Platinum-based catalysts are considered to be the most efficient electrocatalysts for hydrogen evolution reactions due to their extremely fast reaction rate and high exchange current density.However,the high cost and scarcity of this catalyst greatly hinder its widespread application.Therefore,the development of inexpensive and efficient electrocatalysts for the hydrogen evolution reaction has become the most significant issue currently facing.At present,two-dimensional materials have been widely used in catalytic research of hydrogen evolution reaction due to their large specific surface area,many active sites,good stability,and low cost.In this paper,we investigated the catalytic activity of P-or S-doped graphdiyne and Ti₂CO₂@MoS₂ heterostructures for the hydrogen evolution reaction,and the results are as follows:（1）Through density functional theory calculations,we introduce P or S heteroatoms to activate the inert basal planes of graphite.Thereby enhancing its catalytic activity for the hydrogen evolution reaction.We designed fourteen graphdiyne doping modes including interstitial and substitutional.The results show that these doped graphdiynes exhibit rather negative cohesive energy,which indicates the high stability of the doped system.Significant charge transfer occurs between the introduced P or S atoms and the graphdiyne,and the electrical conductivity and magnetic properties of the doped graphdiyne are changed to different degrees compared with the initial graphdiyne.The calculation results show that the Gibbs free energy values of I_P1,S_P1,S_S1 and S_S4 sites in the doped graphdiyne system are close to zero,indicating that the doped system has extremely high catalytic activity for hydrogen evolution reaction.Therefore,graphdiyne can be used as an efficient electrocatalyst for hydrogen evolution reaction by adjusting the way and the site of introduction of P or S atoms,which open a new door for advancing the sustainable production of hydrogen.（2）We investigated the catalytic activity of Ti₂CO₂@MoS₂ heterojunctions for hydrogen evolution reaction by first-principles calculations.The results show that the Ti₂CO₂@MoS₂ heterojunction material exhibits good thermodynamic properties and excellent mechanical and electronic properties.The binding energy indicates that the heterojunction has high stability.The Gibbs free energy values of the sites on the B side and B-in side in the Ti₂CO₂@MoS₂ heterojunction system are close to zero,indicating that the heterojunction has a fairly high catalytic activity for the hydrogen evolution reaction.Therefore,by constructing a Ti₂CO₂@MoS₂heterojunction,it can be employed as an efficient electrocatalyst for the hydrogen evolution reaction,providing a new research strategy for promoting the sustainable production of hydrogen.