Abstract: Isolated dual-atom catalysts (DACs) exhibit remarkable oxygen reduction reaction (ORR) activity due to their unique structural configurations. However, precisely regulating the electronic structure of DACs at the atomic scale and gaining an in-depth understanding of the synergistic mechanisms between bimetallic sites remain significant challenges. Herein, we employ a reliable polystyrene microsphere template-mediated strategy to fabricate a honeycomb-like porous carbon with phosphorus-doped di-nuclear coordination sites (Fe₂N₅P-HPC), where the introduction of additional Fe and P sites enables precise modulation of the electronic structure of the active centers. Density functional theory calculations reveal that the interaction between two charge-asymmetric iron atoms induces electron redistribution at the active sites, leading to increased electron occupancy above the Fermi level, which signifies weakened antibonding orbitals. This effectively activates the O-O bond and facilitates OH* desorption, thereby accelerating the reaction kinetics. Furthermore, the hierarchical porous structure of the honeycomb-like carbon spheres significantly enhances mass transport. As a result, Fe₂N₅P-HPC delivers exceptional ORR performance, with a half-wave potential as high as 0.906 V, surpassing the benchmark Pt/C system. Accordingly, the assembled Zn-air battery achieves a maximum power density of 225 mW cm^-2 and maintains stable operation for over 500 h. This discovery provides valuable insights into the precise regulation of electronic structures in DAC active sites and advances the understanding of catalytic synergy mechanisms.

Key words: The dual-atom catalysts, Oxygen reduction reaction, d-band center modulation, Zinc-air batteries