CeO₂/CoNiP Heterojunction as Excellent OER Electrocatalysts in Alkaline Seawater Effectively Suppresses Chloride Corrosion and Cobalt Leaching

Developing efficient and stable oxygen evolution reaction (OER) catalysts for seawater electrolysis is vital for large-scale hydrogen production. However, traditional catalysts suffer from metal dissolution and chloride corrosion in saline environments. To overcome these limitations, this work presents a CeO2/CoNiP heterostructured electrocatalyst grown on nickel foam. The catalyst was synthesized via hydrothermal treatment, phosphorization, and electrodeposition. Characterization revealed a flower-like CeO2-coated CoNiP structure with abundant active sites and strong interfacial coupling. Electrochemical tests showed low overpotentials (249 mV at 10 mA·cm–2), excellent stability over 250 h, and enhanced kinetics compared with benchmark catalysts. Mechanistic analyses demonstrated that CeO2 promotes *OH adsorption, prevents Co2+ leaching, and repels Cl– due to its negative surface charge under alkaline conditions. This work offers a promising strategy for designing corrosion-resistant electrocatalysts, highlighting the synergistic effects of CeO2 integration in enhancing both the activity and durability for seawater electrolysis.