Synergistic multiphase FeMo oxides and N-doped carbon heterojunctions on Ni foam: A durable and high-efficiency OER electrocatalyst

Efficient, durable non-precious OER electrocatalysts are essential for clean energy conversion. Here, we in situ construct a Ni-foam-supported composite comprising multiphase metal oxides (FeMoO₄, MoO₂, and Fe₂O₃) coupled with graphdiyne-derived N-doped carbon. Interfacial metal–nitrogen coordination promotes electron transport and tunes the electronic structure of metal active centers, leading to markedly enhanced OER activity. In 1.0 M KOH, the catalyst requires overpotentials of only 254 mV and 299 mV to deliver 10 and 100 mA cm−2, respectively, and maintains stable operation for 120 h at 100 mA cm−2. The strong electronic coupling across the oxide/carbon heterojunction provides abundant active sites, improved conductivity, and accelerated reaction kinetics. This work highlights an effective interface-engineering strategy for high-performance OER heterojunction catalysts.