Built‐in Electric Field in Ru/CoP Bifunctional Electrocatalyst Enhances Hydrazine‐Assisted Water Splitting

Abstract Electrocatalytic hydrazine‐assisted water splitting, incorporating the hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR), offers a promising avenue for hydrogen production. Herein, a Ru/CoP heterostructure is introduced, which enhances bifunctional catalytic activity through interfacial interaction induced by the built‐in electric field between Ru nanoparticles and CoP nanosheets. This interaction optimizes the adsorption of intermediates and facilitates improved HER performances by weakening the strong adsorption of active hydrogen species (*H) on Ru and enhancing *H coverage on CoP through hydrogen spillover. Additionally, this electron interaction promotes the adsorption of N 2 H 4 and its subsequent dehydrogenation, vital for HzOR activity. The heterostructure's significant reduction in required potentials for both reactions underscores its efficiency and potential economic benefits over traditional systems. Furthermore, the study validates the feasibility of using this approach for practical applications in sustainable hydrogen production, emphasizing its lower operational costs and enhanced catalytic stability and activity. This work not only showcases the practical applications of Ru/CoP but also underscores the broader applicability of heterostructure strategy in designing efficient bifunctional electrocatalysts.