Core function and mechanism of electrospun carbon nanofiber aerogels/CNTs for accelerating electron transfer efficiency in microbial fuel cell

The sluggish extracellular electron transfer efficiency by traditional two-dimensional anodic materials greatly restricts the application of microbial fuel cells (MFCs). Three-dimensional electrospun carbon nanofiber aerogels (ECNFAs) demonstrate exceptional performance in electrocatalytic energy conversion. However, the effect of components like carbon nanotubes (CNTs) in ECNFAs on power generation performance in MFCs remains largely unknown. This study confirmed that a higher amount of CNTs (7 %) resulted in a higher power density in ECNFAs/CNTs-7 modified MFC (1539.4 mW m −2 ) compared to ECNFAs/CNTs-5 (5 % CNTs, 1426.2 mW m −2 ) and ECNFAs/CNTs-3 (3 % CNTs, 1181.9 mW m −2 ), and it was 2.6 times higher than carbon cloth (CC, 596.1 mW m −2 ). In addition, ECNFAs/CNTs-7 anode showed the highest coulombic efficiency (23.1 %) and lowest electron transfer resistance (9.6Ω). Higher amounts of CNTs in ECNFAs/CNTs-7 attracted more compact biofilm formation and enriched the electroactive bacteria ( Geobacter ) at the MFC anode, contributing to enhanced extracellular electron transfer efficiency and organic contaminant decomposition. The ECNFAs/CNTs facilitated the electron transfer efficiency in MFC through the 3D-scaffold structure and the abundant conductive CNTs. It provided sufficient surface and facilitated extracellular electron transfer activity for electroactive bacteria. This study demonstrated the feasibility and mechanism of ECNFAs/CNTs in promoting power generation in MFCs, thereby guiding the highly efficient recovery of residual energy from wastewater.