Layered Porous Ring-Like Carbon Network Protected Feni Metal Atomic Pairs for Bifunctional Oxygen Electrocatalysis and Rechargeable Zn-Air Batteries

Bimetallic atom catalysts with ultra-high oxygen electrocatalytic activity can achieve mutual promotion and synergistic effects between adjacent metal active centers to exhibit superior multifunctional catalytic activity compared to single metal atomic catalysts. Herein, we introduce FeNi atom pairs (P-FeNi-NPC) protected by hierarchical porous annular carbon grids using a mediator-assisted "MOFs-derived strategy". Introducing the multi-block copolymer P123 enables uniform metal ions confinement and dispersion. Subsequent thermal decomposition forms a "planetary-ring-like" carbon framework to anchor the bimetallic atomic pairs in the active region. The uniform distribution of adjacent Fe-N4 and Ni-N4 active sites enhances the catalytic activity and stability. P-FeNi-NPC exhibits excellent oxygen reduction/evolution reactions (ORR/OER) activities with a ΔE value of 0.705 (E1/2 = 0.845 V, Ej=10 = 1.55 V). Theoretical calculations revealed that FeNi sites on nitrogen-doped carbon frameworks with specific curvature fine-tuned d-band center energies and balance free energy of oxygen-containing intermediates. This work provides a versatile method for advanced bifunctional catalyst synthesis, with implications for Zn-air batteries development.