Tailoring ORR Activity in Fe−N−C Catalysts through Phosphorus Incorporation

Graphical Fe−N−C catalysts, doped with phosphorus, show improved ORR activity. Fe-NPC catalyst exhibits high metal loading, excellent ORR performance (onset potential of 1.00 V, half-wave potential of 0.864 V), and promising application in Zn-air batteries (758.8 mAh g −1 Zn ). DFT calculations reveal that phosphorus enhances O 2 activation and reduces the energy barrier for the rate-determining step. Atomically dispersed iron and nitrogen co-doped carbon materials (Fe−N−C) represent promising non-precious metal catalysts for the oxygen reduction reaction (ORR), offering potential alternatives to noble metal-based benchmarks. In our study, we investigated the influence of phosphorus doping on the catalytic activity of Fe−N−C. The experimental research demonstrate that the doping of phosphorus significantly enhances the ORR activity. Specifically, the resulting Fe-NPC exhibits high metal loading and excellent ORR activity in 0.1 M KOH with an onset potential of 1.00 V and a half-wave potential of 0.864 V. Density functional theory (DFT) simulations reveal that phosphorus improves the electrocatalytic activity by activating O2 molecules and reducing the energy barrier (the hydrogenation reaction *OH→H2O) of the rate-determining step. Furthermore, Fe-NPC exhibits promising application prospects as an air cathode in Zn-air batteries, delivering a high maximum discharge power density of 180.3 mW cm −2 and outstanding discharge specific capacity (758.8 mAh g −1 Zn ) at a discharge current density of 10 mA cm −2 .