Surface conversion derived core-shell nanostructures of Co particles@RuCo alloy for superior hydrogen evolution in alkali and seawater

Hydrogen evolution reaction (HER) in alkali involves higher energy barriers and slow reaction kinetics due to involving water dissociation process. Catalysts with proper surface properties are highly needed to optimize the surface binding energy with reaction intermediates and enhance intrinsic catalytic activity. Herein, we present an effective strategy to construct a self-standing catalyst with core-shell structure, which is composited of metallic Co nanoparticles coated by RuCo alloy layer with optimized surface properties. The Ru attracts electrons from Co and optimizes the surface electronic structure. Theoretical calculations demonstrate that the water dissociation barrier on the Co surface is decreased from 0.65 eV to 0.58 eV after alloying with Ru. Experimental results reveal that the synthesized Co@RuCo-3 features highly efficient catalytic activity together with good stability at large current densities for HER in alkali, as well as in alkaline seawater and pure seawater. A structure engineering strategy is developed to construct core-shell structure for significantly enhanced hydrogen evolution reaction performance of metallic Co in alkali and beyond by surface layer alloying with Ru. Experimental work combined with theoretical calculations were used to analyze the structure-property changes of metallic Co and reveal the relationship between them and intrinsic catalytic activity for hydrogen evolution. • Present an effective strategy to improve alkaline HER performance of Co. • Controllable coating MOF layers on nanomaterials. • A self-standing catalyst with core-shell nanostructure is constructed. • Self-standing Co@RuCo exhibits good long-term stability (100 h) at 500 mA cm −2 .