Ampere-Level Oxygen Evolution Boosted by Asymmetric Fe–O–Ni Coordination in Roll-to-Roll Synthesized NiFc–Metal–Organic Framework

Transition-metal-based catalysts with asymmetric coordination structures are promising candidates for industrial oxygen evolution reactions. However, the large-scale synthesis of catalysts with precisely constructed asymmetric coordination structures is still challenging. Herein, we developed an industry-compatible roll-to-roll combustion technology to synthesize NiFc–MOFs with reasonably constructed asymmetric Fe–O–Ni coordination. Owing to the modulated electronic spin states, regulated adsorption configurations of oxygen-containing intermediates, and charge redistribution, the as-prepared NiFc–MOF achieved ultralow overpotentials of 196 mV and 257 mV at η10 and η1000, respectively. The long-term stability evaluation of catalysts in a three-electrode system demonstrates excellent durability of 2000 h at 2 A cm–2. Further, the assembled anion exchange membrane water electrolyzer (AEMWE, NiFc–MOF||R–Ni) operated at a current density of 1 A cm–2 achieved high overall water splitting with a low cell voltage of merely 2 V and maintained outstanding durability for over 500 h under ambient atmosphere. More importantly, the NiFc–MOF maintained high stability for over 250 h at 1 A cm–2 in simulated seawater. This study offers a reliable pathway to the large-scale synthesis of low-cost NiFe-based catalysts for ampere-level oxygen evolution in both pure and seawater.