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

Abstract

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.