Interfacial Electronic Modulation in Synergistic FeNi–FeNC Hybrid Catalysts with Tuned d-Band Centers for Efficient and Durable Zinc–Air Batteries

FeNC materials are promising nonprecious metal catalysts for zinc–air battery (ZAB) air cathodes. However, their bifunctional catalytic performance is limited by excessively strong adsorption of oxygen intermediates. Here, we constructed a hybrid catalyst consisting of FeNi alloy nanoparticles anchored on a nanocubic FeNC support, denoted as FeNi@FeNC. Strong interfacial coupling between FeNi and FeNC facilitates electron transfer from the alloy to the support. This leads to a downshift of the d-band center and increased electron occupancy of the Fe eg orbitals, thereby optimizing the adsorption energy of oxygen intermediates. Owing to this electronic structure modulation, FeNi@FeNC shows exceptional bifunctional oxygen electrocatalytic performance, including an oxygen reduction reaction (ORR) half-wave potential of 0.9 V, an oxygen evolution reaction (OER) overpotential of 337 mV at 10 mA cm–2, and excellent durability. When applied in a rechargeable ZAB, the catalyst achieves a peak power density of 222.44 mW cm–2 and maintains stable operation for over 500 h. This study demonstrates an effective strategy for interfacial electronic modulation, providing a new approach for developing high-performance bifunctional electrocatalysts for zinc–air batteries.