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

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 (P_max) 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 234 mV and the maximum stabilization time was 4 days. 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.