Nano-structure cathode catalysts for improving Microbial fuel cell performance

Platinum-reduced graphene oxide- graphite nanocomposite (Pt/ RGO/gr) and Pt free catalysts, graphene nanosheets (GNSs), MnO2 and RGO/MnO2 were synthesized and investigated as cathode catalysts for oxygen reduction reaction (ORR) with the Platinum as a benchmark. Electrochemical and morphological characters of the synthesized catalysts were studied using cyclic voltammetry and transmission electron microscopy (TEM). Power densities produced from MFC closed circuit operation using catalysts on the cathodes were about 68 times more than those obtained using graphite electrode. Although, there was slightly reduction of 5.8% in MFC power density (from 170mW/m(2) to 160 mW/m(2)) when Pt nanoparticles were loaded on RGO nanosheet compared to Pt/C cathode, by replacing the precious- Pt catalyst with other catalytic materials, a significant reduction in power density was observed. For RGO based cathode, the MFC performance decreased by 31.1% (from 170mW/m(2) to 117 mW/m(2) ) and the percent of reduction reached 48.5% (from 170mW/m(2) to 88 mW/m(2)) for MnO2 based cathode MFC. However, in RGO/MnO(2 )nano-composite cathode MFC, the percent of reduction in power density was 26.4% (from 170 mW/m(2) to 125 mW/m(2)). It can be concluded that, RGO nanosheet loaded with Pt nanoparticles could be a good start for finding an alternative economic and effective cathode.