Selective OH − Adsorption and Cl − Repulsion on Cr‐Ni Oxide Supported Single Ir‐Atom for Efficient and Stable Seawater Oxidation

ABSTRACT The competitive adsorption of Cl − over OH − presents a major challenge for seawater electrolysis, as it causes severe anode corrosion and low activity, thereby restricting the practical hydrogen production. Herein, chromium‐nickel oxide supported single iridium atom (Ir SA @Cr 2 O 3 /NiO) catalyst was rationally designed, which enables selective OH − adsorption over Cl − for efficient and stable seawater oxidation. Electrochemical evaluations reveal that the resultant Ir SA @Cr 2 O 3 /NiO exhibited outstanding activity for the oxygen evolution reaction (OER), delivering an overpotential of only 215/279 mV at 10/100 mA cm −2 in alkaline seawater electrolytes. The anion‐exchange membrane seawater electrolyzer (AEMSWE) with an Ir SA @Cr 2 O 3 /NiO anode requires a low voltage of only 1.87/2.09 V to reach 500/1000 mA cm −2 . Impressively, the AEMSWE maintains continuous operation at 500 mA cm − 2 for over 1200 h with an ultra‐low degradation rate of 19.83 µV h − 1 , representing two‐orders of magnitude lower than that of an Ir‐NiO anode (4880 µV h − 1 ). Comprehensive in‐situ analysis and density functional theory calculations verified that Cr 2 O 3 effectively modulates the electronic states of the Ir sites, thus enhancing OH − adsorption, suppressing Cl − ‐induced corrosion, and ultimately accelerating both the OER kinetics and selectivity. This work provides new insights for developing highly selective and stable anodes for seawater electrolysis.