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.