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 H₂ production is an imperative matter of utmost practical significance but grand challenge remains. Herein, drawn inspiration from a spontaneous hydrazine‒H₂O galvanic cell configured on a low-valence Ru single atoms-loaded Mo₂C electrode (Ru_SA/v-Mo₂C), an alternative H₂ energy solution utilizing self-powered electrochemical hydrazine splitting (N₂H₄ → 2H₂ + N₂) instead of the stereotyped electricity-consumed water splitting for green H₂ production is proposed. This solution highlights a pH-decoupled hydrazine‒H₂O 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 H₂ 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 H₂ production systems. The success of Ru_SA/v-Mo₂C 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 H₂ production free from both external energy and feedstock inputs, opens up a new horizon on way of the ultimate H₂ energy solution.