Fe-Bi Diatomic Sites with Interactive Regulation for Enhancing Oxygen Reduction Activity and Selectivity

Rational design of heteronuclear dual‑atom catalysts with strong electronic coupling and spatial complementarity for highly selective 4e – oxygen reduction reaction (ORR) remains a significant challenge in electrocatalysis. Herein, a catalyst, Fe–Bi diatomic structures anchored in a cellulose-derived activated carbon matrix (FeBiDA@CC), was obtained for ORR, in which the Fe and Bi atoms exerted a synergistic effect through strong electronic coupling. Bi modulates Fe's spin and electronic structure, while Fe promotes Bi electron polarization and activation of outer shell electrons. The Fe–Bi spatial distance in the dual metal sites geometrically matches O 2 bond length, optimizing modes of adsorption and activation to facilitate the preferred 4e – ORR pathway and improve catalytic stability. FeBiDA@CC exhibits a half-wave potential of 0.93 V, an electron transfer number of 3.92–4.00, and a current loss of only 7.2% after 100 h for ORR. Liquid and flexible zinc-air batteries based on FeBiDA@CC as a cathode catalyst demonstrate outstanding peak power densities of 200.5 and 96.6 mW cm –2, respectively, alongside excellent long-term cycling stabilities of 10,800 and 438 cycles, respectively. This work offers a novel perspective for electronic structural regulation and design of p -block element-based catalysts, opening new possibilities for the design of catalysts in the energy storage field.