Fundamental understanding of nitrogen in biomass electrocatalysts for oxygen reduction and zinc-air batteries

Summary: Exploring high-efficiency catalysts for oxygen reduction reactions (ORRs) is essential for the development of large-scale applications of fuel cell and metal-air batteries technology. The as-prepared Fe-NC-800 via polymerization-pyrolysis strategy exhibited superior ORR activity with onset potential of 1.030 V vs. reversible hydrogen electrode (RHE) and half-wave potential of 0.908 V vs. RHE, which is higher than that of the Pt/C catalyst and most of other Fe-based catalysts. The different d-band center values can be attributed to the influence of different N-doped carbon, leading to the adjustment in the ORR activity. In addition, Fe-NC-800-based Zn-air battery showed better electrochemical performance with a high discharge specific capacity of 806 mA h g−1 and a high-power density of 220 mW cm−2 than that of the Pt/C-based battery. Therefore, the biomass Fe-NC-800 catalyst may become a promising substitute for Pt/C catalysts in energy storage and conversion devices.