Iron containing carbon fibers exhibiting increased electron transfer and electroactive biofilm loading

Sluggish extracellular electron transfer between microorganisms and electrodes has posed a significant challenge in the industrialization of microbial fuel cells (MFCs). Iron compound anodes boost MFC output power, but the underlying mechanisms that govern this enhancement have remained largely unexplored. Herein, we utilize polyacrylonitrile and ferrocene as raw materials to produce iron-incorporated carbon nanofiber materials as MFC anodes, employing electrostatic spinning and high-temperature carbonization. The application of ferrocene enables the introduction of iron into the fibers, which significantly promotes bacterial enrichment and electron transfer. The electroactive biofilm loading and number of live bacteria increase significantly on the fiber with high iron content, facilitating the formation of a continuous biofilm. The carbon nanofiber derived from a PAN/ferrocene composite with a 5:1 wt ratio exhibits optimal performance, attributed to the iron content. This material significantly outperforms carbon fabric, delivering a 13-fold enhancement (1296 mW m −2 ) in maximum power density when utilized as the anode in MFCs. We have examined the interfacial electron transfer process in MFCs, and determined that it is influenced by variations in iron content and fiber diameter. These findings offer valuable insights into the design of fiber electrodes for MFCs and other devices used in bio-electrochemical systems.