Performance of a microbial fuel cell using MnO2 as cathode catalyst

Abstract

Microbial fuel cells are electrochemical devices that use microorganisms as catalysts to produce electricity. Oxygen is the most used electron acceptor in the cathodic reaction of these systems, due to its abundance in the environment and high redox potential; however, the slow kinetics in oxygen reduction constitutes a limitation. Platinum (Pt) is the most widely used catalyst to accelerate the oxygen reduction reaction, but its high cost makes its use on a large scale impossible. In this study, the performance of manganese dioxide (MnO2) as a cathodic catalyst in an H-type microbial fuel cell was examined. The MnO2 layer on the carbon fiber surface was deposited by simply immersing the carbon in an aqueous KMnO4 solution. The microbial fuel cell was characterized by polarization and power curves. A maximum power peak of 6.09 mW/m2 was obtained with a current density of 22 mA/m2, showing that MnO2 can be a low-cost alternative to be used as catalytic material in the cathode of these devices.