Power generation from a biocathode microbial fuel cell biocatalyzed by ferro/manganese-oxidizing bacteria

The abiotic cathodes usually require a catalyst such as Pt to enhance power production, increasing the cost and lowering the operational sustainability. In this paper, the performance of a biocathode microbial fuel cell biocatalyzed by ferro/manganese-oxidizing bacteria was investigated. A scanning electron microscopy with an energy-dispersive spectrometer (SEM-EDS) was used to characterize the cathode and analyze the element of cathode. The amount of ferro/manganese-oxidizing bacteria in the biocathode was examined. In batch-fed systems, the maximum open circuit voltage (OCV) was between 700 and 800 mV and the maximum cell potential difference was higher than 600 mV with an external resistance of 100 Ω. The maximum power density was 32 W m−3 MFC for batch-fed systems (20–40% Coulombic yield) and 28 W m−3 MFC for a continuous system with an acetate loading rate of 1.0 kg COD m−3 day−1. The results of SEM-EDS clearly showed that cathode was impregnated with iron and manganese. The amount of ferro/manganese-oxidizing bacteria was (7.5–20.0) × 105 MPN mL−1 in the biocathode. Biocathodes alleviate the need to use noble catalysts for the reduction of oxygen, which step forward towards large-scale application of MFCs.