Self‐Regenerating 3D Protective Network Breaks the Activity‐Stability Trade‐Off for Industrial Oxygen Evolution Electrocatalysis

ABSTRACT In industrial alkaline water electrolysis (AWE), the long‐term operational stability of oxygen evolution reaction (OER) electrocatalysts under harsh conditions—including high current densities, concentrated alkaline electrolytes, and elevated temperatures—often takes precedence over intrinsic catalytic activity. Nevertheless, existing strategies aimed at enhancing catalyst stability remain insufficient. Herein, we propose a stability‐oriented alloy design strategy based on incorporating corrosion‐resistant Cr into a dual‐phase MnFeCoNiMo high‐entropy alloy. Notably, thermodynamically driven forces promote the spontaneous enrichment of Cr within the Mo‐rich domains. Subsequent selective dealloying enables the in situ formation of a self‐assembled, non‐occlusive 3D (Cr, M)O x ‐enriched protective network. Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) and electron probe microanalysis (EPMA) reveal the continuous self‐regenerating behavior and dynamic structural reorganization of this network during long‐term operation, which effectively reconciles the classic activity–stability trade‐off. As a result, the nanoporous (np) HEA‐CrMo electrode exhibits OER overpotentials of 184 mV at 10 mA cm −2 and 252 mV at 100 mA cm −2 , and sustains stable operation for over 5000 h at 1000 mA cm −2 in 6.0 M KOH. Furthermore, its scalability is demonstrated in a commercial alkaline water electrolyzer with an effective reaction area of 70.9 cm 2 during a 15‐day accelerated stress test.