Boosting microbial fuel cell performance with Co-N_x doped carbon nanotubes/graphene biomimetic anode composites

Enhancing the performance of microbial fuel cells (MFCs) for sustainable energy generation requires innovative anode designs that facilitate efficient extracellular electron transfer (EET). This study presents a biomimetic approach to anode fabrication, developing a hierarchical Co-N_x doped carbon nanotube/reduced graphene oxide (ZnCo/rGO@CC) composite inspired by the EET mechanisms of c-type cytochromes. The composite leverages the synergistic effects of Co-N_x active sites, mimicking heme groups, and a three-dimensional porous structure to promote bacterial colonization and electron transfer. MFCs equipped with the ZnCo/rGO@CC anode achieved a maximum power density of 3.27 W/m² and a startup time of 1.68 days, significantly outperforming traditional carbon cloth anodes (1.49 W/m² and 2.50 days, respectively). Further demonstrating its potential for sustainable waste valorization, the MFC system was successfully operated using sugarcane bagasse as a fuel source, exhibiting a power density of 1.58 W/m². Electrochemical analyses and microbial community characterization confirmed enhanced EET kinetics, selective enrichment of Geobacter (79.73 %), and robust biofilm formation on the ZnCo/rGO@CC anode. This biomimetic anode design, coupled with the utilization of sugarcane bagasse, offers a promising strategy for developing sustainable and efficient bioelectrochemical systems for cleaner energy production.