Microbial Fuel Cells: Nanomaterials Based on Anode and Their Application

Microbial fuel cells (MFCs) exhibit great potential to generate power through organic wastewater treatment. Limitations have restricted the advanced development of MFCs, including low power density, expensive electrode materials, and the challenge to manufacture MFCs in large scale. However, the introduction of advanced anode materials, especially porous and nanostructured materials, is believed to be an effective way to solve the problems, as they can promote bacteria extracellular electron transfer (EET) because of their unique physical, chemical, and electrical properties. Nanostructured materials, including carbon nanotubes (CNTs), graphene, activated carbon fiber, metal, metal oxides and conductive polymers, show many appreciable properties such as good conductivity, large specific surface area, and excellent catalytic activity. Additionally, nanomaterials with unique electrochemical properties provide strong charge interactions with organic compounds and the direct electrochemistry process between bacteria and the anode. This Review comprehensively focuses on the recent development of modification of nanostructured anode materials in view of crucial intrinsic factors to enhance electricity output. Furthermore, the enhanced performance of MFCs and the corresponding known mechanism is also discussed, which enables active bacteria to facilitate electron transfer. Finally, promising strategies to modify anode nanomaterials for future research are presented.