Silicon‐modulated NiFeOOH enables stable oxide‐pathway oxygen evolution under high‐current‐density operation

Stabilizing oxygen evolution catalysts under high‐current‐density operation remains a key challenge for alkaline water electrolysis, where reaction kinetics, mass transport, and structural degradation are strongly coupled. Herein, we report a SiO 2 ‐modified NiFeOOH electrocatalyst that enables sustained oxygen evolution via the oxide path mechanism (OPM) by concurrent regulation of surface structure and electronic states. Silicon incorporation reconstructs surface topography and stabilizes high‐valence Ni/Fe active sites, while mitigating gas‐bubble accumulation and metal dissolution under demanding conditions. Operando spectroscopic combined with density functional theory calculations reveal that Si modulation lowers the energetic barrier for direct OO coupling along the OPM pathway and suppresses degradation pathways. The catalyst delivers an overpotential of 300 mV at 500 mA·cm −2 with stable operation for over 120 h, achieving overall water splitting at 1.74 and 1.87 V in a membrane flow cell. This works provides engineering insights into stabilizing oxide‐pathway electrocatalysis under high‐rate electrolysis.