Recent Advances in the Development of Noble Metal-Free Cathode Catalysts for Microbial Fuel Cell Technologies

The accelerating growth of the global population and the depletion of conventional energy resources have intensified the dual challenges of water scarcity and sustainable energy production. Microbial fuel cells (MFCs) have emerged as a promising bioelectrochemical technology capable of simultaneously treating wastewater and generating renewable electricity. Their performance is strongly dependent on electrode materials, particularly cathodes, which govern the kinetics of the oxygen reduction reaction (ORR) and overall energy conversion efficiency. Therefore, in order to improve the electro-kinetics of ORR, it is necessary to use catalysts with specific catalytic properties. An ideal catalyst for ORR must combine fast kinetics, high conductivity, high durability, and cost-effectiveness. Although platinum-based electrodes remain the most efficient ORR catalysts, their scarcity and prohibitive cost are hindering their commercialization. Therefore, research has focused on viable alternatives, such as metal oxides, perovskites, heterojunction composites, and emerging carbon-based materials, paving the way toward highly effective energy conversion and industrial-scale implementation of MFCs.