Dual-anion synergistic protection of NiFe layered double hydroxide for durable alkaline seawater oxidation

Seawater electrolysis is promising for green hydrogen production but suffers from chloride-induced anodic corrosion. Herein, a dual-anion synergistic protection strategy is proposed for durable alkaline seawater oxidation over V₂O₅ nanolayer coated NiFe layered double hydroxide nanosheets on Ni foam (V₂O₅@NiFe LDH/NF). During seawater oxidation process, the surface V₂O₅ component is reconstructed into adsorbed VO₄^3– species as an anion-enriched protective interface capable of electrostatically repelling Cl^– and mitigating chloride attack. In parallel, the interlayer CO₃^2– confined within NiFe LDH acts as an internal anionic barrier, suppressing Cl^– penetration into the LDH galleries and inhibiting its adsorption on catalytically active sites. The cooperative action of external VO₄^3– protection and internal CO₃^2– shielding endows V₂O₅@NiFe LDH/NF with robust catalytic activity and exceptional durability, delivering an overpotential of 370 mV at 1000 mA cm^–2 and maintaining stable operation for 1000 h under industrial-level current density. Furthermore, an anion-exchange membrane electrolyzer assembled with V₂O₅@NiFe LDH/NF as the anode and Pt/C/NF as the cathode requires only 2.02 V to achieve 500 mA cm^–2 and operates continuously for 1000 h. This study provides a rational dual-anion interfacial engineering strategy for developing durable electrodes under harsh chloride-containing environments.