Nitrogen-doped porous carbon fiber with enriched Fe2N sites: Synthesis and application as efficient electrocatalyst for oxygen reduction reaction in microbial fuel cells

•A porous carbon fiber with abundant Fe2N sites (Fe2N/NPCF) was developed as high performance ORR catalyst for MFCs.•In situ pyrolysis under NH3 atmosphere of MIL-53(Fe) in electrospun fibers is critical for the construction of Fe2N sites.•The synergetic effect of abundant Fe2N and hierarchical porous structure with pyrrolic nitrogen endues Fe2N/NPCF superior catalytic performance to commercial Pt/C.•The Fe2N/NPCF catalyst exhibits higher maximum power density and better long term stability than that of commercial Pt/C in single chamber MFC.