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

Abstract 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 VO43– species as an anion-enriched protective interface capable of electrostatically repelling Cl– and mitigating chloride attack. In parallel, the interlayer CO32– 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 VO43– protection and internal CO32– 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.