Fe2N Enhanced Carbon Fiber Anodes in Microbial Fuel Cells: Improving Power Density and Operational Durability
摘要
Microbial fuel cells (MFCs), as an emerging green-energy technology, have shown considerable promise in the renewable energy field. However, their performance and large-scale application are limited by the low efficiency of extracellular electron transfer (EET) between microorganisms and electrodes, as well as the poor adhesion of electroactive biofilms at the anode interface. Developing highly efficient anode electrocatalysts is crucial for improving MFC performance. In this study, Fe-MOF (MIL-53), polyacrylonitrile (PAN), and polystyrene (PS) were used as electrospinning precursors. Through electrospinning, pre-oxidation, and high-temperature carbonization under N2/NH3 atmospheres, an in-situ Fe2N nanoparticle-doped carbon-fiber anode electrocatalyst, denoted as MIL-53-CF-II, was prepared. The incorporation of MIL-53 endowed MIL-53-CF-II with a hierarchically porous architecture and a large specific surface area. Co-doping with N and Fe introduced abundant surface-active sites (such as Fe–Nx moieties). The in situ-formed Fe2N nanoparticles exhibited excellent electrocatalytic activity and biocompatibility, while the mesopores and the rich pyridinic and pyrrolic nitrogen species in the fibers promoted flavin adsorption. Collectively, these features promoted both mediated and direct extracellular electron-transfer pathways. Consequently, the optimized MIL-53-CF-II anode delivered a maximum power density of 933~mW~m-2 in an MFC, which is $∼$9 times that of the pristine carbon-fiber anode. This work presents a synthesis route toward high-performance anode materials for MFCs, improving electroactive biofilm adhesion and EET, and offers a new strategy to boost the electricity generation performance of MFCs.
