Unveiling In Situ Reconstruction for Dynamically Enhanced Hydrogen Spillover Effect in Electrocatalytic Hydrogen Evolution Process

Abstract The widespread application of water electrolysis is hindered by the inefficient hydrogen evolution reaction (HER) kinetics at industrial‐scale current density. Hydrogen spillover offers a promising strategy to circumvent thermodynamic limitations of volcano diagrams, while its implementation on binary‐component systems remains complex nanomaterial engineering to overcome sluggish interfacial proton migration. Here, an in situ electrochemical reconstruction strategy is reported to optimize hydrogen spillover pathways, which is verified on classic tungsten oxide‐based catalysts (Ru/WOx) with hydrogen spillover effect. Operando characterization and control experiments confirm dynamic oxidation of Ru species during HER operation, which is accompanied with facilitated proton transformation and insertion in WOx lattice. The theoretical calculations reveal that the in situ reconstruction of catalyst dilutes interfacial electron density and lowers thermodynamic barriers for hydrogen migration, thus leading to thermo‐neutral RuO _x /WO ₂ interfacial sites. The reconstructed catalyst achieves a low overpotential of 317 mV at 1000 mA cm ⁻² in alkaline media, with exceptional stability over 500 h. This work elucidates the interplay between in situ reconstruction and proton transfer dynamics, providing new insights for the design of electrocatalysts.