Self-constructed dynamic hydroxyl multi-level chloride-resistant catalytic interfaces of NiFeCoAlSm for industrial-grade overall seawater splitting.

Driven by the practical demand for industrial-scale alkaline seawater electrolysis, chloride-induced corrosion and insufficient stability at high current densities remain critical challenges. Herein, a quinary NiFeCoAlSm high-entropy alloy (HEA) was synthesized by electrodeposition, followed by selective anodic dealuminization for 60 min to obtain a chloride-resistant bifunctional HEA electrocatalyst. The partial dealuminization process regulates the electronic structure and induces a dynamic hydroxyl-rich interface. Density functional theory (DFT) calculations reveal optimized OH- adsorption and suppressed Cl- adsorption on the reconstructed surface. Sm further strengthens the metal-hydroxyl (MOH) structure and stabilizes the catalytic interface. In alkaline seawater, the catalyst delivers an oxygen evolution reaction (OER) overpotential of 356 mV at 500 mA cm-2 and operates stably for over 1000 h, while achieving stable hydrogen evolution reaction (HER) performance at 1000 mA cm-2 for over 100 h. Anion exchange membrane water electrolyzer (AEMWE) for seawater electrolysis assembled with this electrode reaches 500 mA cm-2 at 2.06 V with long-term durability. This work provides a strategy for developing efficient and corrosion-resistant catalysts for industrial-scale seawater electrolysis.