Highly Efficiency Seawater Electrolysis Guided by Coordinating Catalysis of Oxygen Evolution Reaction

Abstract Seawater electrolysis emerges as a promising technology for hydrogen (H ₂ ) production, however, the low selectivity of electrocatalysts for oxygen evolution reaction (OER) is a long‐standing challenge, which is caused by the chlorine evolution reaction (CER) or hypochlorite formation on the anode, leading to the catalyst corrosion and environmental pollution. Here, the principles of coordination chemistry are proposed, and realized using the FeMn Metal–Organic Framework (MOF) based catalysts for addressing such a challenge. The developed catalysts have the preferential interaction between metal active sites and oxygenated reactants to promote oxygen evolution over chlorine evolution, which ensures a remarkably high selectivity of ≈99% toward oxygen evolution in seawater, while suppressing ClER and hypochlorite formation. Furthermore, the FeMn‐MOF catalyst demonstrates long‐term stability in 500 h of seawater electrolysis tests. The successful operation of FeMn‐MOF catalyst in a zero‐gap electrolyzer at 300 mA cm ⁻² and an industrial alkaline seawater electrolyser (ASWE) stack (area 235.5 cm ² anode area in total) at 24 A achieves a new break‐through in the decomposition performance of industrial seawater electrolysis.