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

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.