Enhancement of bioelectricity generation by synergistic modification of vertical carbon nanotubes/polypyrrole for the carbon fibers anode in microbial fuel cell.

Abstract Enhancing microbial electrocatalysis through novel anode design is essential to the efficient and stable operation of microbial fuel cells. Carbon fibers modified by the vertical carbon nanotubes/polypyrrole composites can give full play to their advantages, exhibiting excellent conductivity of the vertical carbon nanotubes and good biocompatibility of the polypyrrole. The carbon nanotubes are vertically grown on the carbon fibers by the chemical vapor deposition method, increasing the transfer efficiency of extracellular electron transfer. And then pyrrole is in-situ polymerized on the exterior and interior of the vertical carbon nanotubes, which can not only avoid direct contact between the vertical carbon nanotubes and electricigens to reduce the damage of the vertical carbon nanotubes to electricigens, but also enhance the positive electricity of anode. The modification of the vertical carbon nanotubes/polypyrrole for mesophase pitch carbon fibers anode improves the electricity generation performances of the microbial fuel cells. In this study, the obtained maximum power density is 1876.62 mW m−2, which is approximately 2.63-fold higher than unmodified carbon fiber brush anode. The results show that the vertical carbon nanotubes/polypyrrole composite anode has demonstrated the high potential for the use of microbial fuel cells. Highlights • The modification of vertical carbon nanotubes/polypyrrole enhances the bioelectricity generation performance of MFCs. • The vertical carbon nanotubes improve the transfer efficiency of extracellular electron transfer. • Polypyrrole significantly increases the anode biocompatibility and shortens MFCs start-up time. [ABSTRACT FROM AUTHOR]