Porous carbon codoped with inherent nitrogen and externally embedded cobalt nanoparticles as a high-performance cathode catalyst for microbial fuel cells.

• A N-doped porous carbon electrocatalyst embedded with cobalt nanoparticles is synthesized. • The maximum power density of Co/N-C-800 is 1738 ± 40 mW m−2, 44.5% higher than that of Pt/C. • Pyrolysis promotes the reduction of cobalt and expansion of surface area. • Graphitic-N, Co(0) and cobalt oxide synergistically promote exposure of active sites and speed 4-electron transfer process. High-performance porous carbon embedded cobalt nanoparticles derived from chitosan, which is applied to microbial fuel cell as cathode catalyst, is prepared using one-step high-temperature calcining method. The nitrogenous porous carbon embedded cobalt nanoparticles treated at 800 °C (Co/N-C-800) is a high-efficiency electrocatalytic material due to its low electron transfer resistance and high exchange current density. The maximum power density of Co/N-C-800 is 1738 ± 40 mW·m−2, which is 44.5% higher than that of Pt/C (1203 ± 18 mW·m−2). In fact, the high specific surface area of 335.08 m2·g−1 for the porous carbon can provide an adequate amount of oxygen and exposed active sites that contribute to the oxygen reduction reaction. Moreover, the graphitized carbon, graphitic nitrogen and cobalt nanoparticles are all involved in the improvement of oxygen reduction reaction performance. In brief, porous carbon with external cobalt nanoparticles is a promising catalytic cathode due to its low cost, facile synthesis and excellent performance. [ABSTRACT FROM AUTHOR]