Molten-salt-mediated synthesis of porous Fe-containing N-doped carbon as efficient cathode catalysts for microbial fuel cells

Exploring precious-metal-free cathode electrocatalysts toward oxygen reduction reaction (ORR) is a prerequisite for advancing the commercialization of microbial fuel cell (MFC). We herein report a molten-salt-mediated method to prepare a cost-effective Fe-containing N-doped carbon (denoted as Fe/C/Ns-900) as ORR electrocatalyst. Systematic characterization via a variety of techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), demonstrates the Fe/C/Ns-900 holds a porous structure and has the characteristic of iron (Fe) and nitrogen (N) doping. The Fe/C/Ns-900 was studied as an electrocatalyst for ORR and showed excellent activity in neutral electrolyte, inspiring us to establish a MFC using the cost-effective Fe/C/Ns-900 as cathode catalyst. The optimum MFC device showed a maximum power density of 900 +/- 5 mW m(-2), outperforming the MFC made using the Pt/C as cathode catalyst.