Bond Electronegativity as Hydrogen Evolution Reaction Catalyst Descriptor for Transition Metal (TM = Mo, W) Dichalcogenides

Two-dimensional transition metal (TM) disulfides have emerged as promising nonprecision catalysts for hydrogen evolution reactions (HERs) because they have exhibited tunable electrocatalytic activity at different sites. However, the design of efficient catalytic sites is still limited to the trial-and-error stage, largely due to the lack of rational design principles. Here, we present a universal principle to evaluate HER catalytic activity of the various MoS₂ structures such as TM-substitute, S-vacancy, Mo-edge, and S-edge, based on high-throughput first-principles calculations. We reveal that their catalytic activity has a fundamental relationship with the bonding characteristics of the local environment, such as valence electron number, bond electronegativity, and bond distance. Some catalytic activity predicted by the design principle is consistent with the available experimental data. The design principle elucidates the intrinsic nature of electrocatalysis is electron transfer capacity from a catalytic structure to a hydrogen atom. More importantly, the design principle based on MoS₂ can be extended to other transition metal disulfides with the same valence electron amounts. Through the design principle, we find many possible catalysts such as Zn@S-vacancy@MoS₂, Zn@Mo-edge@MoS₂, Y@S-edge@MoS₂, Zn/Ag@W-edge@WS₂, Ru/Zn@substitute-W@WS₂, and Pd@S-vacanay@WS₂, which may achieve a highly efficient catalytic activity. These findings provide important insight toward understanding catalytic properties and serve as design principles for new catalysts.