Carbon nanotube-coated stainless steel mesh for enhanced oxygen reduction in biocathode microbial fuel cells

A novel carbon nanotubes (CNTs) coated stainless steel mesh (SSM) electrode has been fabricated by a simple and scalable process and is used as biocathode in microbial fuel cell (MFC) for performance improvement. Examination by scanning electron microscope shows that CNTs are uniformly distributed over the surface of the SSM, thus forming a three-dimensional network structure. The MFC with CNT-SSM biocathode achieves higher maximum power density (147 mW m−2), which is 49 times larger than that (3 mW m−2) produced from the MFC with bare SSM biocathode. Moreover, cyclic voltammetry shows that the microorganisms on the CNTs-SSM biocathode play a major role in oxygen reduction reaction (ORR), and the CNT-SSM biocathode performes better catalytic activity toward ORR than that of SSM biocathode. Additionally, the MFC with CNTs-SSM biocathode has higher Coulombic Efficiency than that of MFC with bare SSM biocathode. In this study, we demonstrate that the use of CNTs-SSM offers an effective mean to enhance the electricity of biocathode MFCs.