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.