Unsaturated bi‐heterometal clusters in metal‐vacancy sites of 2D MoS₂ for efficient hydrogen evolution

Abstract The valence states and coordination structures of doped heterometal atoms in two‐dimensional (2D) nanomaterials lack predictable regulation strategies. Hence, a robust method is proposed to form unsaturated heteroatom clusters via the metal‐vacancy restraint mechanism, which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide. The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites. Among them, the strong binding energy of negatively charged suspended S and O sites for H⁺, as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*, reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation. Whereupon, the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec⁻¹. In brief, this metal vacancy‐induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.