Oxygen Anion-Mediated Electron Pump Suppressed Iron Segregation in Cobalt-Iron Catalyst Boosts Ampere-Scale Seawater Electrolysis

• • The CoFe-NO2−-LDH catalyst sustains over 1000 hours of stable operation at an industrially relevant current density of 1000 mA cm−2 in seawater electrolysis, directly addressing the durability bottleneck for practical deployment. • • Nitrite anion doping induces an electronic pump effect that modulates iron valence states, facilitating high-valence Fe species for OER activation while suppressing oxidative dissolution under high potentials, as confirmed by in situ characterization. • • The nitrite-generated electrostatic repulsion field effectively repels chloride ions, mitigating corrosion and active site segregation, which is critical for long-term operation in chloride-rich seawater. • • Mechanistic studies reveal that nitrite doping weakens Fe–O covalency, suppressing lattice oxygen participation and promoting a stable adsorbate-evolving mechanism, thereby enhancing operational stability without compromising catalytic activity.