Ferricyanide Armed Anodes Enable Stable Water Oxidation in Saturated Saline Water at 2 A/cm2

The direct seawater electrolysis at high current density and low overpotential affords an effective strategy toward clean and renewable hydrogen fuel production. However, the severe corrosion of anode as a result of the saturation of Cl^- upon continuous seawater feeding seriously hamper the electrolytic process. Herein, cobalt ferricyanide / cobalt phosphide (CoFePBA/Co₂ P) anodes with Cap/Pin structure are synthesized, which stably catalyze alkaline saturated saline water oxidation at 200-2000 mA cm^-2 over hundreds of hours without corrosion. Together with the experimental findings, the molecular dynamics simulations reveal that PO₄ ^3- and Fe(CN)₆ ^3- generated by the electrode play synergistic role in repelling Cl^- via electrostatic repulsion and dense coverage, which reduced Cl^- adsorption by nearly 5-fold. The novel anionic synergy endow superior corrosion protection for the electrode, and is expected to promote the practical application of saline water electrolysis.