Preparation of Hierarchical Porous Fe/N Codoped Carbon Nanosheets as Oxygen Reduction Reaction Electrocatalysts for the Zinc-Air Battery

In recent years, Fe–N–C materials have been considered as feasible substitutes for platinum-based catalysts to enhance the oxygen reduction reaction (ORR). However, Fe–N–C catalysts still have specific problems, including poor inherent activity, restricted availability of active sites, and inferior stability. This work presents a simple and efficient method for synthesizing Fe/N codoped hierarchical porous carbon nanosheets using one-step pyrolysis. The optimized Fe–N–C 900 catalyst exhibits excellent ORR performance with an onset potential of 0.958 V and half-potentials of 0.885 V in an alkaline medium, surpassing those of the commercial Pt/C catalyst. In addition, the optimal catalyst demonstrated improved stability and great resistance to methanol. Furthermore, the zinc-air battery constructed from Fe–N–C 900 shows a remarkable power density of 163.65 mW cm^–2 and a specific capacity of 807.80 mA h g_Zn^–1. The electrochemical stability and cycle stability were proven to exceed 400 h at a current density of 5 mA cm^–2. This study offers valuable insights for the development of highly efficient and stable ORR catalysts in the clean energy field.