The synthesis of iron-nitrogen sites embedded in electrospun carbon nanofibers with an excellent oxygen reduction reaction activity in alkaline/acidic media

• Published in: New carbon materials 2023-02, Vol.38 (1), p.154-160
• Main Authors: Xu, Xiang-xiang, Zhang, Nian-chao, Wang, Jun-ying, Wang, Jun-zhong
• Format: Article
• Language: English
• Subjects: Carbon nanofiber; Electrospun; Oxygen reduction reaction
• ISSN: 1872-5805; 1872-5805
• DOI: 10.1016/S1872-5805(22)60649-8

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-C3N4 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-C3N4 to the electrospinning precursor led to the formation of abundant Fe-N species in Fe3+ and Fe2+ valence states, while Fe3C nanoparticles were formed without adding g-C3N4. Compared to Fe3C/CNF prepared without g-C3N4, 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.