Synthesis, Structural, and Morphological Characterizations of Reduced Graphene Oxide-Supported Polypyrrole Anode Catalysts for Improved Microbial Fuel Cell Performances

The conductive polypyrrole (PPy)/reduced graphene oxide (rGO) composites were synthesized through simple, environmentally benign, time and cost efficient, in situ polymerization and bioreduction techniques. The pyrrole monomer effectively adsorbed over the negatively charged GO sheets through electrostatic and π–π interactions was polymerized into polypyrrole in its adsorbed state. The obtained morphological images of the rGO/PPy composite ensured that the entire surface of the active carbon support was covered by PPy. The removal of oxygen functionalities from GO with the aid of Ocimum tenuiflorum extract was ascertained through FT-IR and UV–vis absorption spectroscopic studies. The rGO/PPy composite exhibited higher electrocatalytic oxidation current as evidenced from the cyclic voltammetric analysis. The number of actives sites and continuous carrier channels of the rGO/PPy composite exhibited a maximum MFC power density of 1068 mW/m2, which is almost two-fold higher than that of bare PPy. The strong active carbon support prohibited the swelling and shrinkage of the conductive polymer PPy and provided the strong physico and electrochemical robustness of the rGO/PPy composite, which increased the MFC durability performances up to 300 h. These findings have not only provided fundamental knowledge on the preparation rGO-based composites through a green approach but also have found possible applications in large-scale green energy devices.