Enhanced electrical contact of microbes using Fe3O4/CNT nanocomposite anode in mediator-less microbial fuel cell

A novel Fe3O4/CNT nanocomposite was synthesized and employed for the modification of carbon paper anode in a mediator-less microbial fuel cell (MFC) to enhance its performance. The Fe3O4/CNT composite modified anodes with various Fe3O4 contents were investigated to find the optimum ratio of the nanocomposite for the best MFC performance. The Fe3O4/CNT modified anodes produced much higher power densities than unmodified carbon anode and the 30 wt% Fe3O4/CNT modified anode exhibited a maximum power density of 830 mW/m2. In the Fe3O4/CNT composite modified anode, Fe3O4 helps to attach the CNT on anode surface by its magnetic attraction and forms a multi layered network, whereas CNT offers a better nanostructure environment for bacterial growth and helps electron transfer from E.coli to electrode resulting in the increase in the current production with the catalytic activity of bacteria. The electrocatalytic behavior and all possible mechanism for their better performance are discussed in detail with the help of various structural and electrochemical techniques.