Nitrogen-doped carbon nanofibers anchoring Fe nanoparticles as biocompatible anode for boosting extracellular electron transfer in microbial fuel cells

Sluggish extracellular electron transfer (EET) at the anode interface is the major obstacle to achieving satisfactory power density in microbial fuel cells (MFCs). To boost the EET efficiency, herein the anode electrocatalysts , nitrogen-doped carbon nanofibers anchoring Fe nanoparticles (Fe/N-x@CNFs, x = 0.5, 1, 3, 5), are rationally designed via electrospinning and calcination process. The morphology and structure characterization indicates that the Fe/N-3@CNFs electrocatalyst presents a porous structure with uniformly distributed Fe nanoparticles on the carbon matrix, which offer a large-accessible surface area for electroactive bacteria habitation along with facilitated EET efficiency. Electrochemical measurements demonstrate that the as-fabricated Fe/N-3@CNFs exhibit excellent electrocatalytic activity for the charge transfer on the anode, endowing the cell with a maximum power density of 1873.8 mW m −2 , which is 1.8 and 3.6 times higher than that of Fe@CNFs (1039.2 mW m −2 ) and carbon cloth (519.8 mW m −2 ). The outstanding performance of Fe/N-3@CNFs can be attributed to the increased electronic conductivity of carbon matrix with melamine additives, the enriched electroactive bacteria as demonstrated by high-throughput sequencing, and the released positively charged iron mediators to promote EET efficiency. This investigation introduces an effective method of constructing high-efficient anode electrocatalysts for enhancing the output MFCs performance.