Spatial Heteroatom Modulates Electron Itinerancy of Spinel Lattice for Accelerated Oxygen Catalysis

• • Fe(Sat)-Co3O4 exhibits a 1% lower impedance per Fe atom than Co3Fe(In)O4, directly reducing ohmic losses in electrolyzer stacks and enabling higher current density operation at lower cell voltage. • • The turnover frequency and mass activity are increased by tens of times relative to Co3Fe(In)O4, translating to a proportional reduction in precious metal loading and catalyst cost per kilowatt of hydrogen output. • • Overpotential for the oxygen evolution reaction is reduced by 120 mV at industrial current densities, which corresponds to an approximate 10% improvement in electrolyzer energy efficiency and a commensurate decrease in electricity consumption per kilogram of H2. • • The resistance-free electron delocalization layer formed in Fe(Sat)-Co3O4 establishes a high-speed electron transport channel between the crystal and satellite, mitigating charge accumulation and enabling stable operation at high current densities without degradation.