First-Principles Calculations Of Non-Metal Doped Molybdenum Disulfide For Hydrogen Evolution Reaction

Molybdenum disulfide(MoS2)is considered as a promising catalyst for hydrogen evolution reaction(HER)due to its low cost and catalytic activity at the edge.However,their limited quantity of active sites and poor conductivity have hampered the efficiency of hydrogen production.Non-metallic dopants could lead to a significantly improved activity for hydrogen evolution,however,the origin of their enhancement effect is still not clear.In this work,we investigated the effect of non-metallic dopants on tuning the hydrogen evolution performance of MoS2 by using a density functional theory approach,which help to screen out the non-metal-doped MoS2 with excellent activity.The main points explored out are as follows:1.Except for O-group and halogen elements,other non-metal dopants induce empty electron orbitals with different energy level in the band gap of MoS2,which decreases the energy barrier of electron leap and accordingly increases the electrical conductivity.In addition,Non-metal dopants reduce the saturation of the valence electron orbitals of the S site,which increases the strength of H adsorption at the S site.2.In alkaline environment,the non-metal sites with empty electron orbitals like B,C and Si tend to bond with O in H2O,resulting in chemisorption.While it will weaken the bond strength of OH bonds and promote the dissociation of H2O.3.It was found that the synergistic modification on MoS2 through using nonmetals with different valence electron structures(e.g.C-As co-doping and O-P co-doping)can reduce the energy barrier of the desorption process of OH groups while promoting the dissociation of water molecules,which accelerate the hydrogen evolution kinetics in alkaline environment.Therefore,the availability of non-metal-doped MoS2 on the hydrogen evolution reaction in different environments can be demonstrated,and it is of great theoretical significance and practical application to design catalysts with better catalytic performance for non-metal doped systems.