Revitalizing microbial fuel cells: A comprehensive review on the transformative role of iron-based materials in electrode design and catalyst development

Microbial fuel cells (MFCs) face substantial challenges, including electrode cost, biofouling, and slow kinetics of the oxygen reduction reaction (ORR) at the cathode. This review examines iron-based (Fe-based) materials as electrodes and catalysts, emphasizing their efficacy in pollutant degradation and electricity generation. As anode modifiers, Fe-based materials enhance electrical energy production by improving electron transport, increasing anode voltage, and promoting microbial adhesion. At the cathode, they facilitate a more efficient 4-electron transfer process for the ORR, reducing undesirable hydrogen peroxide formation. This review discusses the impact of Fe and N dispersion, surface, and active site optimization on ORR activity and stability, highlighting the advantages of Fe-based materials in terms of stability, reproducibility, and biocompatibility through multi-element doping and nanoscale interface engineering. These modifications enable Fe-based materials to outperform traditional Pt/C catalysts in power density. The role of microbial communities, including Geobacter and Pseudomonas, in electron transfer and wastewater treatment in Fe-based MFCs is also addressed. Additionally, the potential of artificial intelligence (AI) to optimize operational and catalyst performance in enhancing Fe-based MFC efficiency is explored. This review concludes with a comprehensive assessment of Fe-based materials in MFCs, focusing on their contributions to sustainable energy and water purification by examining bioelectricity generation, fabrication costs, and power output, thereby providing a holistic overview of the advancement of Fe-based materials for environmentally sustainable applications.