WS₂ Moiré Superlattices Supporting Au Nanoclusters and Isolated Ru to Boost Hydrogen Production

Maximizing the catalytic activity of single-atom and nanocluster catalysts through the modulation of the interaction between these components and the corresponding supports is crucial but challenging. Herein, guided by theoretical calculations, a nanoporous bilayer WS₂ Moiré superlattices (MSLs) supported Au nanoclusters (NCs) adjacent to Ru single atoms (SAs) (Ru₁/Au_n-2LWS₂) is developed for alkaline hydrogen evolution reaction (HER) for the first time. Theoretical analysis suggests that the induced robust electronic metal-support interaction effect in Ru₁/Au_n-2LWS₂ is prone to promote the charge redistribution among Ru SAs, Au NCs, and WS₂ MSLs support, which is beneficial to reduce the energy barrier for water adsorption and thus promoting the subsequent H₂ formation. As feedback, the well-designed Ru₁/Au_n-2LWS₂ electrocatalyst exhibits outstanding HER performance with high activity (η₁₀ = 19 mV), low Tafel slope (35 mV dec^-1), and excellent long-term stability. Further, in situ, experimental studies reveal that the reconstruction of Ru SAs/NCs with S vacancies in Ru₁/Au_n-2LWS₂ structure acts as the main catalytically active center, while high-valence Au NCs are responsible for activating and stabilizing Ru sites to prevent the dissolution and deactivation of active sites. This work offers guidelines for the rational design of high-performance atomic-scale electrocatalysts.