Anti‐dissolving High Entropy Phosphorus Sulfide for Efficient and Durable Seawater Electrolysis

Abstract Direct seawater electrolysis is a promising technology for massive green hydrogen production but is limited by the lack of durable and efficient electrocatalysts toward the oxygen evolution reaction (OER). Herein, a high entropy phosphorus sulfide (HEPS) is prepared as a high‐performance OER catalyst for seawater splitting through a simple vacuum high‐temperature sintering method. This catalyst needs overpotentials of merely 245 and 313 mV in alkalized seawater to deliver current densities of 10 and 100 mA cm ⁻² , respectively, and operates continuously for 1200 h in a practical electrolyzer with negligible activity decay, making it one of the best OER catalysts for seawater electrolysis reported to date. Detailed experimental and theoretical analyses reveal that the excellent durability of HEPS originates from the P and S in the material is oxidized and forms an anionic protective layer to repel chloride ions, preventing further corrosion of the material. Meanwhile, the formed V ₂ O _x species can effectively prevent the material from further oxidation. Further, a highly stable and efficient seawater electrolyzer is assembled with the HEPS anode and the Ru@C cathode to demonstrate the practicability of the catalysts.