Oxophilic Regulation Drives the Mechanism Transition of NiOOH Toward the Oxide Pathway for Water Oxidation

ABSTRACT

The adsorbate evolution mechanism (AEM) is limited by the intrinsic linear scaling relationship, and the direct participation of lattice oxygen in the lattice oxygen oxidation mechanism (LOM) often induces structural degradation. To address this challenge, we introduced oxophilic Fe into NiOOH (Fe _0.6 NiOOH) to promote direct coupling of adsorbed oxygen species ( ^* O─O ^* ), thereby inducing the catalytic reaction to proceed via the oxide pathway mechanism (OPM). The oxophilic Fe‐doped catalyst Fe _0.6 NiOOH has a low overpotential of 199 mV at 10 mA cm ⁻² under alkaline conditions and maintains stable operation for over 1200 h at 1 A cm ⁻² with virtually no significant decay. Furthermore, the Pt/C||Fe _0.6 NiOOH electrode pair operated continuously for 1500 h at 1 A cm ⁻² in an anion‐exchange membrane electrolyzer (30 wt.% KOH, 80°C). Advanced in situ spectroscopy combined with density functional theory calculations confirmed that oxophilic Fe incorporation promotes ^* OH adsorption and shortens the Ni─O and Fe─O bonds, thereby facilitating the formation of ^* O radical and promoting the coupling of ^* O─O ^* , ultimately driving the OER pathway toward OPM. This work provides a new strategy for designing highly efficient and stable Ni‐based catalysts and also offers important insights into identifying the optimal reaction pathway for industrial water electrolysis.