Enhancing extracellular electron transfer through selective enrichment of Geobacter with Fe@CN modified carbon-based anode in microbial fuel cells

Abstract Microbial fuel cells (MFCs) have been demonstrated as a renewable energy strategy to efficiently recover chemical energy stored in wastewater into clean electricity by exoelectrogens through a combination of microbial metabolism and electrochemical processes, yet the limited power density limits their application. Here, Fe coped carbon and nitrogen (Fe@CN) nano-material was synthesized by direct pyrolysis of FeCl3 and urea, which was further decorated to fabricate Fe@CN modified carbon paper anode to improve the bioelectrochemical performance of MFCs. With a higher electrochemically active surface area, the Fe@CN modified anode was beneficial for enhancing microorganisms adhesion and extracellular electron transfer (EET). Accordingly, the MFC with Fe@CN modified anode (MFC-Fe@CN) successfully achieved a highest voltage output of 792.76 mV and a prolonged stable voltage output of 300 h. Interestingly, Geobacter species (15.41% abundance) was significantly enriched in the EABs of MFC-Fe@CN, while MFC-CP (unmodified carbon paper anode) favored the other exoelectrogens (Dysgonomonas and Comamonas). This work demonstrated the feasibility of development on anode catalysts for the elaboration of the catalytic principle about interface modification, which may contribute to the practical application of MFC in energy generation and wastewater treatment.