Water dissociation energy variations in hydrogen evolution reaction in transition Metal-doped MoS₂

The electrochemical hydrogen evolution reaction (HER) has attracted significant attention due to its essential role in enabling economical and sustainable hydrogen production through water-splitting. In particular, searches for universal HER electrochemical catalysts have identified two-dimensional (2D) transition metal dichalcogenides (TMDs) as promising candidates. One highly effective strategy for enhancing the efficiency of the HER is transition metal (TM) doping, which modifies the electronic structure of TMDs and activates the reaction sites. Herein, we theoretically interpret the influence of doping on the water dissociation reaction through first-principles calculations for TM-doped MoS₂. Using ΔG_H2O calculations, we performed a systematic analysis of the electrochemical properties of 30 TM-doped MoS₂ systems and found that group 11 TM-doped MoS₂ exhibits the most energetically favorable water dissociation reaction. We also report two key factors that influence the water dissociation reaction, namely, the changes in the charges of sulfur atoms adsorbed with H∗+OH∗ for MoS₂ with early TM dopants, and the structural deformation energy associated with H∗+OH∗ adsorption for MoS₂ with late TM dopants.