Construction of N-doped hierarchically porous carbon catalysts with CoFe alloy via spatial and chemical anchor confinement for oxygen catalytic reaction

This study presents a novel strategy for synthesizing bifunctional oxygen electrocatalysts by embedding CoFe alloy nanoparticles within N-doped hierarchically porous carbon (FeCo@NC) via spatial and chemical confinement effects. Utilizing the mixture of ZIF-67 and iron tetranitrophthalocyanine (FePc-NH2) as precursors, the metal atoms migration and agglomeration are effectively restricted during pyrolysis. By optimizing the Fe/Co atomic ratio, the Fe0.46Co1@NC catalyst achieves exceptional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities, evidenced by a high half-wave potential (E1/2 = 0.86 V vs. RHE), a low overpotential gap (ΔE = 0.74 V), and a limiting current density of 5.8 mA cm-2. Structural characterization confirms uniform dispersion of ∼10–20 nm FeCo alloy nanoparticles encapsulated by graphitic carbon layers, alongside abundant pyridinic/graphitic-N sites and hierarchical porosity (BET: 379 m2 g-1). When assembled in Zn-air batteries, Fe0.46Co1@NC delivers a high open-circuit voltage (1.46 V), a specific capacity of 781 mAh g-1, and a peak power density of 168.4 mW cm-2, which outperforms the Pt/C+RuO₂ benchmarks. This work highlights the synergy between confined alloy nanoparticles and N-doped carbon matrices for advanced energy conversion