Fe-Fe3N composite nitrogen-doped carbon framework: Multi-dimensional cross-linked structure boosting performance for the oxygen reduction reaction electrocatalysis and zinc-air batteries

Taking into consideration the sluggish kinetics of the oxygen reduction reaction (ORR) and the distinct three-phase environment of the electrode, it is crucial to optimize the surface structure of the electrocatalyst. This study employs a sol-gel approach to synthesize a Fe-Fe3N composite three-dimensional nitrogen-doped carbon framework (Fe-Fe3N/3DNC) and utilize it as the electrocatalyst for a zinc-air battery. The material possesses a multi-dimensional cross-linking frame structure comprised of one-dimensional and two-dimensional crosslinks, which effectively reduce the diffusion mean-free path of oxygen. Moreover, the iron-nitrogen site and nitrogen-rich carbon substrate both exhibit exceptional electrocatalytic activity for ORR. Consequently, a conventional liquid zinc-air battery utilizing this material as the air cathode catalyst exhibits a maximum power density of 242.8 mW cm-2, surpassing that of commercial Pt/C. Additionally, DFT calculations further confirm the crucial enhancing influence of Fe3N in the Fe-Fe3N/3DNC composite on ORR. This research provides valuable insights for the development of ORR electrocatalysts with outstanding efficiency.