Activating lattice oxygen in metal oxyhydroxides as durable electrodes for industrial-scale seawater splitting

Electrocatalytic seawater splitting powered by renewable electricity is a promising route for large-scale green hydrogen production, yet remains challenging due to electrode corrosion and competing chlorine evolution at high current densities. Developing robust and efficient anodic catalysts is therefore essential. Here, we show an in-situ growth strategy to transform iron foam into boron-doped cobalt-iron oxyhydroxide (B-FeCoOOH) nanosheets. Boron incorporation and a disordered lattice generate abundant oxygen vacancies, lowering kinetic barriers for water oxidation. The catalyst requires only 325 mV to deliver 1.0 A cm−2 and exhibits less than 2% performance decay after 600 h in alkaline seawater. Mechanistic studies indicate that oxygen vacancies activate the lattice oxygen oxidation mechanism, bypassing the scaling limitations of the conventional adsorbate evolution mechanism. The disordered structure enhances structural flexibility to accommodate dynamic reconstruction, mitigating active site dissolution. This strategy is extendable to other transition metal-based oxyhydroxides, enabling the fabrication of large-area, self-supporting electrodes. This work establishes a general strategy for designing durable catalysts for practical seawater electrolysis. Electrocatalytic seawater splitting enables green hydrogen production but is limited by corrosion and competing chlorine evolution. Here, the authors report a boron-doped iron-cobalt oxyhydroxide catalyst achieving high current density at low overpotential with good stability.