Synergistic hydroxide enrichment and chloride repulsion for Ampere-level stable seawater oxidation

Benefiting from the abundant renewable energy supply in coastal regions, electrochemical seawater splitting for green hydrogen production shows great potential. However, the chloride (Cl⁻)-rich nature of seawater creates a highly corrosive environment, posing a significant obstacle to the anodic stability. Herein, a rationally designed catalyst with multiple protections, containing strong Cl⁻ repulsion, OH⁻ enrichment, and local pH regulation, is applied for robust electrochemical alkaline seawater oxidation (eASO). In the eASO process, Zr will form ZrO_x species acting as Lewis sites during this process, which exhibit a strong affinity toward OH⁻. This effectively mitigates the negative impact of the electrostatic protective layer on OH⁻ transport, enhances the surface OH⁻ coverage, and further promotes phase transformation. In addition, low-valent P^δ− will be oxidized to PO₄³⁻, which subsequently adsorbs onto the surface of active MOOH (M = Co) sites, forming a dual-functional protective layer that provides proton buffering and Cl⁻ repulsion. Overall, such a designed anode achieves a 1500 h stable eASO at 1 A·cm⁻² without any activity degradation, providing a new feasible design strategy for the green seawater-to-H₂ system.