The potential of Co3O4 nanoparticles attached to the surface of MnO2 nanorods as cathode catalyst for single-chamber microbial fuel cell

Abstract

A simple two-step hydrothermal method was used to prepare the cathode catalyst of microbial fuel cell (MFC). MnO₂@Co₃O₄ composite was successfully prepared by in-situ growth of nano-particle-like Co₃O₄ on nano-rod-like MnO₂. The hybrid products had (121), (310), (311), (400) and (511) crystal planes, rod-like and point-like structures were observed. MnO₂@Co₃O₄ nanohybrids were rich in a variety of metallic elements and provided rich electrochemically active sites. The maximum voltage of MnO₂@Co₃O₄-MFC was 425 mV, the maximum stabilization time was 4 d. The maximum output power was 475 mW/m², which was 2.24 times that of Co₃O₄-MFC (212 mW/m²) and 2.63 times of MnO₂-MFC (180 mW/m²). The rod-like structure of MnO₂ could effectively improve the ion flow efficiency and reduce the transfer resistance, and the point-like structure of Co₃O₄ can increase the specific surface area of the complex and provide more active sites.

Keywords: Co(3)O(4); Microbial fuel cell (MFC); MnO(2); Oxygen reduction reaction.