A multi-atom active site carbon catalyst featuring synergistic electronic effects for efficient oxygen reduction in zinc–air batteries

The development of cost-effective and durable electrocatalysts to supplant precious-metal systems for the oxygen reduction reaction (ORR) is paramount for advancing sustainable energy technologies. We introduce a hierarchically structured catalyst composed of Fe, N, and S co-doped carbon nanofibers (Fe-N-S-CNFs), derived from a polyimide self-assembly and subsequent thermochemical treatment. This unique three-dimensional, flower-like architecture affords a high specific surface area, which facilitates rapid mass/charge transport and maximizes the exposure of catalytically active sites. The synergistic electronic modulation among the dopants and the carbon matrix endows the optimized catalyst (Fe-N-S-CNFs-900) with exceptional ORR performance, evidenced by a half-wave potential of 0.84 V that is highly competitive with commercial Pt/C, alongside remarkable durability and methanol tolerance. When integrated into a zinc-air battery as the air cathode, Fe-N-S-CNFs-900 achieves a high open-circuit voltage of 1.48 V and a peak power density of 98 mW cm −2 , outperforming the Pt/C benchmark. Collectively, these findings establish this polymer-derived, multi-element-doped carbon as a highly effective alternative to noble-metal catalysts for advanced electrochemical energy applications. We developed flower-like Fe–N–S co-doped carbon nanoflowers (Fe-N-S-CNFs) with a 3D porous nanosheet architecture. The unique morphology and synergistic Fe–N–S doping endow the catalyst with abundant active sites, high surface area, and optimized electronic structure. The optimized Fe-N-S-CNFs-900 shows excellent ORR activity (E1/2 = 0.84 V), outstanding durability, and methanol tolerance. As a Zn–air battery cathode, it delivers a high open-circuit voltage (1.48 V) and peak power density (98 mW cm −2 ), outperforming Pt/C. • Self-assembled Fe–N–S carbon nanoflowers provide a robust 3D porous framework. • Synergistic Fe–N–S coordination optimizes electronic structure and boosts ORR activity. • Zn–air batteries achieve high voltage, peak power, and long-term stability beyond Pt/C.