Hierarchical porous iron and nitrogen co-doped carbons (HP-Fe-N-Cs) as efficient cathode catalysts for oxygen reduction reaction (ORR) in neutral media are reported. The HP-Fe-N-Cs are prepared by using polypyrrole as nitrogen source and poly(vinyl alcohol) (PVA) hydrogel-based composites as insitu templates. In studying the effect of the iron and the hierarchical porous structure on the nitrogendoped carbon support for ORR, we find that HP Fe N Cs show more positive onset potential, higher cathodic current density, and higher electron transfer number for the ORR in neutral media than ironfree hierarchical porous nitrogen-doped carbon (HP-N-C) and non-hierarchical porous iron and nitrogen co-doped carbon (Fe N-C), highlighting the importance of the iron and the hierarchical porous structure for improving the ORR performance. Furthermore, HP-Fe-N-Cs show better durability than the commercial Pt/C catalysts in neutral media, and the microbial fuel cells (MFCs) equipped with HP-Fe-N-Cs catalysts on cathodes exhibit comparable power outputs with those of MFCs with commercial Pt/C cathode catalysts. (c) 2014 Elsevier B.V. All rights reserved.