Ampere‐Level Membrane‐Free Bipolar Ammonia Electrosynthesis with Faradaic Efficiency Exceeding 100% on a Surface‐Reconstructed NiFe‐Hydroxide

Abstract

Abstract Awaking the force of materials for specific efficacy by precise electronic modulation remains a fundamental challenge in catalysis. Herein, we transform ordinary NiFe‐layered double hydroxide (NiFe‐LDH) into a high‐performance NO 3 − ‐to‐NH 3 electrocatalyst via cathodic electrochemical restructuring, which effectively induces oxygen vacancy (O v ) clusters preferentially localized around low‐valence Ni sites. The resultant restructured NiFe‐LDH (NiFe‐LDH‐R) demonstrates excellent concentration‐universal NH 3 electrosynthesis activity in 1 M KOH, notably sustaining high Faradaic efficiencies (FEs, 88.5%–95%) across a broad potential range and attaining an ampere‐level current density (−1.46 A cm −2 ) together with a remarkable yield rate of 104.1 mg NH3 h −1 cm −2 . In situ spectroscopic analyses reveal boosted hydrogenation kinetics and a thermodynamically favorable NOH pathway for NiFe‐LDH‐R, which is further decoded by theoretical calculations indicating that synergized O v /Fe and low‐valence Ni sites, respectively enhance NO 3 − adsorption and directional active hydrogen (*H) supply, thus streamlining overall energy barriers. Moreover, a new‐style membrane‐free bipolar electrosynthesis system is established, which enables unprecedent NH 3 FEs exceeding 100% and scalable NH 3 valorization into 4.1 g of methenamine. This study rekindles power of electrochemical restructuring in catalyst advance and pioneers a new paradigm for energy‐efficient electrochemical NH 3 production and fixation.