Power generation using spinel manganese–cobalt oxide as a cathode catalyst for microbial fuel cell applications

► We used spinel manganese–cobalt (Mn–Co) oxides for microbial fuel cells (MFCs) applications. ► We prepared Mn–Co oxides by a solid state reaction with different initial Mn/Co atomic ratios. ► Mn–Co oxide with Mn/Co atomic ratio of 2 was the most effective catalyst toward ORR due to the highest BET surface area. ► Mn–Co oxide catalysts exhibited a great potential to replace platinum as a cathode catalyst for MFCs. This study focused on the use of spinel manganese–cobalt (Mn–Co) oxide, prepared by a solid state reaction, as a cathode catalyst to replace platinum in microbial fuel cells (MFCs) applications. Spinel Mn–Co oxides, with an Mn/Co atomic ratios of 0.5, 1, and 2, were prepared and examined in an air cathode MFCs which was fed with a molasses-laden synthetic wastewater and operated in batch mode. Among the three Mn–Co oxide cathodes and after 300h of operation, the Mn–Co oxide catalyst with Mn/Co atomic ratio of 2 (MnCo-2) exhibited the highest power generation 113mW/m2 at cell potential of 279mV, which were lower than those for the Pt catalyst (148mW/m2 and 325mV, respectively). This study indicated that using spinel Mn–Co oxide to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs.