Abstract:
Metal-nitrogen carbon catalysts have received great attention in the field of gas-evolving electrocatalysis due to their high activity, large specific surface area and efficient gas diffusion paths. A solution of porphyrin iron, g-C
3N
4 and polyacrylonitrile in N,N-dimethylformamide was sonicated and electrospun into doped polyacrylonitrile nanofibers (NFs), and the NFs were then stabilized and carbonized at 900 °C to prepare Fe-N/CNF catalyst for oxygen reduction reaction (ORR). It was found that the addition of g-C
3N
4 to the electrospinning precursor led to the formation of abundant Fe-N species in Fe
3+ and Fe
2+ valence states, while Fe
3C nanoparticles were formed without adding g-C
3N
4. Compared to Fe
3C/CNF prepared without g-C
3N
4, the Fe-N/CNF catalyst presents an 4e
− improved oxygen reduction reaction activity in both alkaline and acidic media. Furthermore, as a cathode in Zn-air batteries, the Fe-N/CNF catalyst exhibits high performance with an open-circuit voltage of 1.49 V, a power density of 146 mW cm
−2 and a specific capacity of 703 mAh g
−1. This work suggests a way to prepare metal-nitrogen-carbon catalysts for energy-related electrocatalytic applications.