ABSTRACT Transition metal oxides (TMOs) are promising alternatives to precious‐metal electrocatalysts for the oxygen evolution reaction (OER), but their low intrinsic activity and high overpotentials present a critical challenge. Therefore, how to improve the intrinsic activity of TMO remains a challenge. Herein, Fe 3 O 4 /NiO heterointerfaces were constructed on ultra‐thin carbon nitride substrates via interface engineering, yielding a hybrid catalyst denoted as Fe 3 O 4 /NiO@CN‐1 for alkaline oxygen evolution reaction (OER). ICP analysis results show that the metal loading is extremely low, with 0.20 wt% Fe and 0.33 wt% Ni. Benefiting from interfacial coupling and charge‐transfer/adsorption behavior, Fe 3 O 4 /NiO@CN‐1 exhibits a better OER performance with an overpotential of 305.73 mV at the current density of 10 mA cm −2 and a current density of 124.7 mA cm −2 in 1 M KOH. Despite the trace metal content, its activity possesses certain competitiveness among non‐precious‐metal catalysts, highlighting the key role of Fe 3 O 4 /NiO heterointerfaces on ultra‐thin CN. The LSV curve remains nearly unchanged after 1000 cyclic voltammetry scans and stable operation is maintained for ≥22 h, suggesting promising stability under laboratory conditions. This study provides a feasible strategy to develop high‐performance non‐precious‐metal OER catalysts on CN supports via heterointerface engineering with minimized transition‐metal usage.
Zhang et al. (Fri,) studied this question.