CeO <i> _x </i> ‐Induced Spatial and Electronic Modulation for General Direct Oxo Coupling in Transition Metal Hydroxides

ABSTRACT Electrochemical water splitting has emerged as a sustainable paradigm for hydrogen generation, where sluggish kinetics of the oxygen evolution reaction (OER) catalyzed by transition metal‐based materials remain the critical bottleneck. Herein, we present a strategy that anchors CeO x nanoparticles (∼2 nm) onto two‐dimensional Ni(OH) 2 nanosheets, enabling dual modulation of spatial configuration and electronic states to accelerate O–O coupling. Spatially, interfacial lattice distortion between CeO x and Ni(OH) 2 optimizes Ni–Ni dual‐metal sites with reduced interatomic spacing. Electronically, dynamic modulation through reversible Ce 3+ /Ce 4+ redox cycling positions Ce as an electronic regulation hub, stabilizing Ni species at the catalytically favorable +3 oxidation state through Ce─O─Ni interactions. This synergistic effect shifts the pathway from adsorbate evolution mechanism (AEM) to oxide pathway mechanism (OPM). The prepared CeO x @Ni(OH) 2 achieves an overpotential of 152 mV at 10 mA cm −2 and operates continuously over 2000 h with limited performance decay. When integrated into an alkaline anion exchange membrane water electrolyzer (AEMWE), it requires 1.91 V to attain 1 A cm −2 and maintains stable operation for 450 h. This OPM activation strategy shows potential applicability across CeO x ‐loaded transition metal hydroxides, including Ni(OH) 2 , Co(OH) 2 , NiCo, and NiFe layered double hydroxides, offering a promising approach for alkaline OER enhancement.