Boosting Industrial Hydrogen Evolution via OH– Spillover on Ru Single Atoms Enabled by a Hierarchical Ni@Ni3C Core–Shell Architecture

Abstract Developing industrial-grade alkaline hydrogen evolution catalysts remains a critical challenge due to sluggish water dissociation and limited proton availability at the electrode–electrolyte interface. Here, we construct a metastable Ni/Ni3C core–shell structure and anchor atomically dispersed Ru single-atom sites (Ru SAs/Ni@Ni3C) to overcome this bottleneck. In situ studies reveal that Ru sites selectively adsorb hydroxyl species, enabling a dynamic OH– spillover that rapidly refreshes adjacent Ni active sites. Concurrently, an optimized interfacial water network accelerates proton transport. This synergy between Ru single atoms and the non-equilibrium core–shell substrate achieves exceptional activity and stability through a cooperative hydrogen adsorption–desorption cycle. Ru SAs/Ni@Ni3C demonstrated stable operation at 2 A cm–2 for more than 600 h in an anion-exchange-membrane water electrolyzer (AEMWE). These findings establish a generalizable strategy for designing efficient and durable electrocatalysts for alkaline water electrolysis.