Improved bioelectrochemical performance of MnO2 nanorods modified cathode in microbial fuel cell.

Abstract

The property of cathode in the microbial fuel cell (MFC) was one of the key factors limiting its output performance. MnO2 nanorods were prepared by a simple hydrothermal method as cathode catalysts for MFCs. There were a number of typical characteristic crystal planes of MnO2 nanorods like (110), (310), (121), and (501). Additionally, there were great many hydroxyl groups on the surface of nanorod-like MnO2, which provided a rich set of active adsorption sites. The maximum power density (Pmax) of MnO2-MFC was 180 mW/m2, which was 1.51 times that of hydrothermally synthesized MnO2 (119.07 mW/m2), 4.28 times that of naturally synthesized MnO2 (42.05 mW/m2), and 5.61 times that of the bare cathode (32.11 mW/m2). The maximum voltage was 234mV and the maximum stabilization time was 4days. The characteristics of MnO2, including rod-like structure, high specific surface area, and high conductivity, were conducive to providing more active sites for oxygen reduction reaction (ORR). Therefore, the air cathode modified by MnO2 nanorods was a kind of fuel cell electrode with great application potential.