Cerium-Doped NiFe Hydroxides Enabling Hybrid Pathways for Durable Alkaline Water Oxidation under Fluctuating Power

In this work, we present a cerium-substituted NiFe-layered double hydroxide (NiFe-Ce LDH) that synergistically activates both the adsorbate evolution mechanism (AEM) and a localized lattice-oxygen mechanism (LOM) for efficient alkaline water oxidation. Atomic Ce incorporation induces charge redistribution through Ce 4f-O 2p interactions, stabilizing Fe sites and upshifting the O2p band to enable controlled lattice-oxygen redox without structural collapse. In situ ATR-SEIRAS and DEMS measurements confirm the simultaneous formation of *OOH and OO* intermediates, indicating the hybrid pathway. The optimized NiFe-Ce LDH achieves an overpotential of 220 mV at 10 mA cm-2 and sustains 500 mA cm-2 operation for 650 h. In a membrane-electrode assembly electrolyzer, it delivers 20 A for over 800 h with only a 0.1 V increase after 850 h. Under simulated wind-power voltage fluctuations (1.45-2.25 V), the catalyst maintains stable performance and demonstrates potential for sustainable hydrogen production in dynamic energy environments.