Engineered PW<sub>12</sub>-polyoxometalate docked Fe sites on CoFe hydroxide anode for durable seawater electrolysis.

He, Xun; Yao, Yongchao; Zhang, Min; Zhou, Yilei; Zhang, Limei; Ren, Yuchun; Dong, Kai; Tang, Hong et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Seawater electrolysis driven by offshore renewable energy is a promising avenue for large-scale hydrogen production but faces challenges in designing robust anodes that suppress surface chlorine reactions and corrosion at high current densities. Here we report a strategy by selectively docking PW<sub>12</sub>-polyoxometalate (PW<sub>12</sub>-POM) onto Fe sites of CoFe hydroxide anode to modulate the electronic structure of adjacent Co active centers and regulate Cl⁻/OH⁻ adsorption for efficient alkaline seawater oxidation. Our CoFe-based anode achieves low overpotentials, high catalytic selectivity, and notable durability, with continuous operation at 1 A cm⁻² for over 1300 hours and at 2 A cm⁻² more than 600 hours. Theoretical calculations and ex situ/in situ analyses reveal that PW<sub>12</sub>-POM coordination at Fe sites stabilizes Fe, suppresses its leaching, modulates Co acidity, promotes OH⁻ adsorption, and protects metal sites from Cl⁻ corrosion.