Investigation of Fe2N@carbon encapsulated in N-doped graphene-like carbon as a catalyst in sustainable zinc-air batteries

The rational construction of low cost, efficient, and stable oxygen reduction reaction (ORR) electrocatalysts is important for the commercialization of fuel cells and metal-air batteries. In this article, we report an easy and effective soft-template method to in situ assemble Fe2N nanoparticles on the surface of N-doped graphene-like carbon (NC). The prepared Fe2N nanoparticles were covered by a few carbon layers, which promoted the connection of Fe-N-X clusters with graphene to facilitate the formation of Fe-N-C active sites. Fe-N-X and NC units were found to respectively fulfill different functionalities, and commonly afford the sample with excellent performance. The electrochemical data show that the Fe2N@NC composite with high-purity and good crystalline displays a synergistic enhanced catalytic activity for ORR, including a positive onset potential (0.084 V), a half-wave potential (-0.036 V) and a high electron transfer number (similar to 4e(-)), as compared to 20% Pt/C. Additionally, the existence of carbon shells wrapped around Fe2N nanoparticles can restrain their expansion and dissolution. In addition, the as-prepared catalyst was implemented as an air catalyst for zinc-air batteries and was found to display a comparable open circuit voltage of ca. 1.48 V and a maximum power density of 82.3 mW cm(-2). These results demonstrate that the Fe2N@NC catalyst may serve as a good alternative to precious Pt for ORR in practical applications.