A novel one step method was developed to dope nitrogen (N), sulfur (S) and carbon (C) in the Fe nanoparticles-dispersed carbon nanofibers (CNFs) grown over carbide-derived carbon (CDC), using thiourea as the single source of N, S and C. The synthesized N/S-Fe-CNF/CDC electrode was successfully used in a microbial fuel cell (MFC). When tested as the oxygen reduction reaction (ORR) catalyst, the electrode achieved a high current density (2.261 +/- 0.002 mA/cm(2)), high OCP (0.611 +/- 0.005 V), high stability upto 400 cycles, response time of similar to 11 s, electron transfer number in the range 3.73-4.03, and Tafel slopes of -0.0627 and -0.183 V/dec at low and high current densities, respectively. A first order kinetics and a 4e(-) pathway were deduced from the ORR analysis. Notably, the fabricated MFC based on the prepared electrode produced a high current density of 1.3887 +/- 0.002 mA/cm(2), high OCP of 0.626 +/- 0.005 V and maximum power density of 0.238 +/- 0.002 mW/cm(2), attributed to the synergistic effects of heteroatoms, Fe nanoparticles, and CNFs. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.