Ultrastable Seawater Oxidation at Ampere‐level Current Densities with Corrosion‐resistant CoCO3/CoFe Layered Double Hydroxide Electrocatalyst

Abstract Hydrogen is an essential energy resource, playing a pivotal role in advancing a sustainable future. Electrolysis of seawater shows great potential for large‐scale hydrogen production but encounters challenges such as electrode corrosion caused by chlorine evolution. Herein, a durable CoCO 3 /CoFe layered double hydroxide (LDH) electrocatalyst is presented for alkaline seawater oxidation, showcasing resistance to corrosion and stable operation exceeding 1,000 h at a high current density of 1 A cm −2 . The results indicate that CoCO 3 within the electrocatalyst undergoes conversion into CoOOH and releases CO 3 2− during electrolysis. The incorporation of CO 3 2− within its layers and the anchoring of the electrocatalyst's surface prevent the adverse adsorption of chloride ions, enhancing resistance to chloride ion corrosion, thereby protecting the active sites of the electrocatalyst effectively.