Semi‐Crystalline Ruthenium Catalyst for Zero‐Drag Hydrogen Production from Hybrid Alkaline Seawater Electrolysis

Abstract Hydrazine‐assisted hybrid alkaline seawater electrolysis offers a dual‐functional platform for environmentally benign remediation of toxic hydrazine and energy‐autonomous hydrogen generation. Addressing the critical need for simplified system integration, a single‐metal bifunctional catalyst is developed by modulating electronic metal‐support interactions (EMSI) to construct semi‐crystalline Ru domains with metastable crystalline‐amorphous interfaces. The optimized catalyst achieves ultralow overpotentials of 21.5 mV (hydrogen evolution) and 254 mV (hydrazine oxidation) at 10 mA cm⁻ 2 , alongside spontaneous hydrazine decomposition at open‐circuit potential. This synergy enables near‐zero energy input for electrolysis, evidenced by a steep polarization slope (1.235 A cm⁻ 2 V⁻¹), which surpasses conventional hybrid systems. Density functional theory (DFT) calculations reveal that amorphous Ru sites near the interface induce charge redistribution, which partially optimizes the free energy changes associated with adsorption * H and the dehydrogenation process from * N₂H₄ to * N₂H₃. This is accompanied by a transformation of the rate‐determining step into the * N₂H → * N₂ pathway, thereby advancing the kinetics of the bifunctional hydrogen evolution reaction/hydrazine oxidation reaction (HER/HzOR) reactions. The work redefines catalyst design paradigms by leveraging interfacial metastability, bridging pollutant elimination with high‐efficiency hydrogen economies.