Dual-function surface engineering for enhancing anode stability in alkaline seawater oxidation

Although seawater electrolysis holds great promise for green hydrogen production, the persistent challenges of chloride ions (Cl−)-induced chemical corrosion and localized acid etching under high potential severely hinder the lifespan of the anode. Herein, we propose that Os nanoparticles anchored on CoP nanowires supported by Ni foam (Os-CoP/NF) acts as a dual-protection anode with proton-buffering and Cl−-repelling capabilities to simultaneously inhibit corrosion during seawater oxidation. The self-released PO43− not only repels Cl− but also mitigates the gradual decrease in local pH over reaction time. Meanwhile, the dispersed Os sites can bind with Cl− to form Os–Cl species, which inhibit chlorine chemistry corrosion via the common-ion repulsive effect. The designed anode achieves stable operation for up to 4500-h ampere-level real seawater electrolysis. Notably, this protection strategy safeguards the active sites from corrosion both during operation and after the shutdown of system. The assembled membrane electrode also exhibits a lifespan of 500 h for both continuous electrolysis and intermittent electrolysis, demonstrating an electrode design concept with broad application potential. Seawater electrolysis for green hydrogen is hindered by chloride-induced corrosion and local acidification of anodes. Here, the authors report an osmium-decorated cobalt phosphide anode that buffers protons and repels chloride, enabling stable ampere-level seawater electrolysis for 4500 h.