Reconstructing Hydrogen‐Bond Network on High‐Entropy Phosphide for Efficient and Durable Seawater Electrolysis

ABSTRACT The development of efficient and corrosion‐resistant electrocatalysts for the oxygen evolution reaction (OER) in alkaline seawater is critical for sustainable hydrogen production, yet the regulatory mechanism of interfacial hydrogen‐bond networks and the anti‐corrosion effect of dual anions in seawater electrolysis remain poorly understood. Here, we report a nanoporous high‐entropy metal phosphide (CoNiFeCrMo) 2 P (np‐HEMP), prepared by rapid melt‐quenching followed by chemical dealloying, which exhibits exceptional OER activity and durability in chloride‐containing electrolytes. The np‐HEMP achieves a low overpotential of 273 mV in alkaline natural seawater at 10 mA cm −2 and maintains excellent stability for over 290 h at 200 mA cm −2 in an anion‐exchange‐membrane seawater electrolyzer. In situ spectroscopy, density functional theory (DFT), and ab initio molecular dynamics (AIMD) calculations reveal that the self‐reconstructed high‐entropy (oxy)hydroxide surface promotes rapid hydroxide transport and the formation of a strong hydrogen‐bond network, thereby accelerating the intrinsic OER kinetics. Concurrently, the in situ formed PO 4 3− /MoO 4 2− dual‐anion interface effectively repels Cl − through an electrostatic shielding effect, suppressing chloride corrosion and side reactions. This work provides atomic‐level insights into the role of high‐entropy materials in regulating interfacial chemistry for efficient seawater splitting.