A Hydrazine‒Water Galvanic Cell‐Inspired Self‐Powered High‐Rate Hydrogen Production via Overall Hydrazine Electrosplitting

Abstract Exploring advanced electrolysis techniques for attaining scene‐adaptive and on‐site green H ₂ production is an imperative matter of utmost practical significance but grand challenge remains. Herein, drawn inspiration from a spontaneous hydrazine‒H ₂ O galvanic cell configured on a low‐valence Ru single atoms‐loaded Mo ₂ C electrode (Ru _SA /v‐Mo ₂ C), an alternative H ₂ energy solution utilizing self‐powered electrochemical hydrazine splitting (N ₂ H ₄ → 2H ₂ + N ₂ ) instead of the stereotyped electricity‐consumed water splitting for green H ₂ production is proposed. This solution highlights a pH‐decoupled hydrazine‒H ₂ O primary battery with notable open‐circuit voltage of 1.37 V and energy density up to 358 Wh g _N2H4 ⁻¹ , which powerfully propels an alkaline hydrazine splitting cell, leading to bilateral H ₂ harvest with a remarkable rate of 18 mol h ⁻¹ m ⁻² , i.e., 403.2 L h ⁻¹ m ⁻² , setting a new record for the self‐sustaining electricity‐powered H ₂ production systems. The success of Ru _SA /v‐Mo ₂ C for this solution is further decoded by tandem theoretical and in situ spectroscopic studies, cross‐verifying a Ru‒Mo dual‐site synergy in streamlining the overall energy barriers, thereby enhancing the kinetics of electrode reactions. This pioneering work, showcasing electrochemical H ₂ production free from both external energy and feedstock inputs, opens up a new horizon on way of the ultimate H ₂ energy solution.