A facile method for preparation of efficient oxygen reduction catalyst for a microbial fuel cell cathode

摘要

A facile preparation method for efficient oxygen reduction catalyst was suggested by examining three different approaches, which are microwave heating of a precursor solution (MS), dried precursor powder (MD), and autoclave heating of precursor solution (AS). The highest reduction peak current observed in (-0.034 mA) in cyclic voltammogram was obtained from the MS catalyst. However, the reduction peak current of the AS and the MD catalysts were 94.12% and 50%, of the MS catalyst, respectively. The surface with the MS catalyst consisted of small catalyst particles embedded in MWCNT strands, and its oxygen content was 4.67%, which was considerably lower than those of the surfaces (25.62 similar to 38.86%) with the MD- and the AS catalysts, wherein large lump aggregations of catalyst compounds were observed. The MFC with MS catalyst cathode had very low activation and ohmic resistances (7.7 Omega, 5.0 Omega) at maximum power density, and its MFC with the MS catalyst cathode were as low as 7.7 Omega, 5.0 Omega, respectively, at maximum power density and it's limiting current (19.6 mA) was considerably higher than the MD catalyst (2.75 mA) and the AS catalyst (10.2 mA) cathodes. The maximum power density of the MFC with MS catalyst cathode was 1,425 mW/m(2), which was quite higher than those of the MFCs with MD catalyst (270 mW/m(2)) and AS catalyst (833 mW/m(2)) cathodes. This result shows that microwave heating (MS) of the catalyst precursor solution is the most feasible method for preparation of an efficient oxygen reduction catalyst for MFCs.