MnO synergizes with FeC–FeN in carbon nanofibers to boost oxygen reduction for zinc–air batteries

Abstract

Incorporating metal oxides to optimize the charge distribution of iron species is an effective strategy, which develops efficient electrocatalysts for oxygen reduction. In this work, we fabricated a carbon-based catalyst (Fe₄Mn₄-NC-800) through the process of electrostatic spinning and high-temperature calcining, which involved co-doping with MnO, FeC, and FeN in carbon nanofibers. This one-step synthesis approach effectively increased the exposure of active sites, leading to improved catalytic reaction kinetics. The Fe₄Mn₄-NC-800 catalyst displays exceptional oxygen reduction reaction (ORR) performance (E_onset = 1.06 V and E_1/2 = 0.86 V) and robust long-term stability in 0.1 M KOH. Acid washing experiments revealed the enhancement mechanism of MnO on the catalytic process of FeC and FeN. Furthermore, the zinc–air battery with Fe₄Mn₄-NC-800 assembly displays superior open circuit voltage (∼1.51 V), specific capacity (∼793 mA h g_Zn⁻¹), and power density (∼170.8 mW cm⁻²) compared to Pt/C, indicating its feasibility in practical applications. Therefore, this study has proposed an efficient and promising method for the preparation of ORR catalysts, which could be a breakthrough in material design.