Flexible Palladium-Carbon Nanotubes-Graphite-PVC Film for Application as an Appropriate Electrocatalyst in Oxygen Reduction of Microbial Fuel Cell

A microbial fuel cell (MFC) is a device that converts chemical energy into electrical energy through the catalytic processes of microorganisms. In this study, a graphite-based flexible film was obtained by adding of zinc powder to a mixture of multi walled carbon nanotubes-graphite powder-polyvinyl chloride (PVC) and then selectively replacing of palladium (Pd) with Zn in a solution containing PdCl2. Surface morphology studies showed that the flexible film has a porous structure, where palladium and carbon nanotubes as uniform conduction channels are present in composite of the film. Electrochemical studies also showed that porous Pd/MWCNTs-Graphite-PVC film as a cathode in MFC at 22-ohm resistance has a current density and power density of 568 mA/m2 and 18500 µW/m2, respectively (compared to 191 mA/m2 and 810 µW/m2 for Pt foil), showing excellent electrochemical activity of the modified film for O2 reduction. Improved electrocatalytic behavior of the modified film can be attributed to porous structure of film and synergistic effect between CNTs and palladium. The method presented in this research can be employed as a favorite method for preparing of suitable electrocatalysts based on commercial graphite powder in the microbial fuel cells.