Superhydrophilic S‐NiFe LDH by Room Temperature Synthesis for Enhanced Alkaline Water/Seawater Oxidation at Large Current Densities

Abstract Developing high‐performance oxygen evolution reaction (OER) electrocatalysts that can operate stably at large current densities in seawater plays a crucial role in enabling large‐scale hydrogen production, however, it remains a significant challenge. Herein, sulfur‐doped NiFe layered double hydroxide nanosheet (S‐NiFe LDH) grown on a 3D porous nickel foam skeleton is synthesized through electrochemical deposition and ion‐exchange strategies at room temperature as high‐performance, highly selective, and durable OER electrocatalyst for seawater electrolysis at large current density. The incorporation of S can enhance the conductivity, promote structural reconstruction to form highly active oxyhydroxides, as well as improve the anti‐corrosion ability of chloride ions. Furthermore, due to its unique self‐supporting structure and superhydrophilicity, which provide abundant active sites and promote efficient bubble release, the optimized electrocatalyst demands a minimal overpotential of 278 and 299 mV to generate 1000 mA cm −2 in alkaline freshwater/seawater, respectively, confirming its excellent OER activity. Meanwhile, the synthesized electrocatalyst also demonstrates exceptional stability in both media, as it maintains stable performance for a duration of 200 h at 500 mA cm −2 . The present work offers an efficient strategy and innovative viewpoint for developing efficient OER electrocatalysts for seawater electrolysis.