High power generation in mixed-culture microbial fuel cells with corncob-derived three-dimensional N-doped bioanodes and the impact of N dopant states

High power generation with low capital cost is still a great challenge for the practical application of microbial fuel cells. In this work, the efficient three-dimensional N-doped macroporous carbon foam anodes were fabricated using naturally abundant nitrogenous corncobs and successfully adopted in microbial fuel cells with mixed-culture inoculation. The optimized three-dimensional N-doped macroporous carbon foam bioanode achieved a power density of 4.99 ± 0.02 W/m2 and a current density of 12.30 ± 0.01 A/m2, which represents the best performance among the reported carbon-based ones for microbial fuel cells to date. Such enhancements would likely be due to not only the good biocompatibility of three-dimensional N-doped macroporous carbon foams for the enrichment of electroactive Geobacter, but also the enhancement of extracellular electron transfer efficiency of the Geobacter with anode doping of N atoms especially for pyrrolic N, as indicated by density functional theory calculation. This study provides valuable insights for the design and optimization of low-cost carbon-based anodes for high-performance microbial fuel cells.