Tailoring the electronic architecture of FeP by Mo doping for advanced bifunctional oxygen electrocatalysis in Zn–air batteries

Abstract

The development of efficient and durable non-precious-metal bifunctional oxygen electrocatalysts remains a central challenge for advancing metal–air battery technology, largely due to the intrinsic activity–stability trade-off originating from the unfavorable adsorption energetics of oxygen intermediates. Herein, we report a targeted electronic structure reconfiguration strategy for Fe2P via precise Mo doping, producing a high-performance catalyst for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The incorporated Mo atoms act as atomic-scale electron donors that transfer electron density into the Fe–P framework, forming Fe–P–Mo bonding networks that induce charge redistribution and an upshift of the Fe d-band center toward the Fermi level, thereby rebalancing the adsorption energetics of the oxygen intermediates (*O, *OH, and *OOH) toward the Sabatier optimum and lowering the energy barriers of the rate-determining steps of both the ORR and the OER. The optimized catalyst exhibits remarkable bifunctional performance, delivering a half-wave potential of 0.87 V for the ORR and an OER potential (Ej=10) of 1.56 V versus RHE at 10 mA cm−2. This yields a small potential gap (ΔE) of 0.69 V, comparable to that of the noble-metal benchmark (Pt/C + RuO2, 0.68 V). In a zinc–air battery, the catalyst achieves a peak power density of 170.2 mW cm−2 and stable cycling for more than 700 h, outperforming its Pt/C + RuO2-based counterpart (142.9 mW cm−2 and ∼140 h). This work clarifies the mechanistic link between doping-induced electronic modulation and electrocatalytic performance, offering design principles for next-generation energy conversion materials.