Boosting the cathode function toward the oxygen reduction reaction in microbial fuel cell using nanostructured surface modification

Abstract

AbstractProduction of bioelectricity via microbial fuel cells (MFCs) may become an important source of energy in the near future due to the possibility of extracting electric current from a wide range of organic wastes. In this study, several nanostructures, such as platinum (Pt)‐reduced graphene oxide nanocomposite, graphene nanosheets, MnO2, and MnO2/RGO, were synthesized, characterized, and investigated as cathode catalysts for oxygen reduction reaction. The prepared catalysts were tested in a single‐chamber microbial fuel cell with anaerobic bacterial mixed culture. Power density produced from MFC closed circuit operation using the nanoengineered catalysts were about 68 times more than those obtained using the classical graphite electrodes. Moreover, there was a slight reduction of 5.8% in power density (from 170 to 160 mW/m2) when Pt nanoparticles were loaded on the RGO nanosheets compared to Pt/C cathode. By replacing the precious Pt catalyst with other nanomaterials, a significant reduction in power density was observed. For RGO‐based cathode, the MFC performance decreased by 31.1% (from 170 to 117 mW/m2) and the percent of reduction reached 48.5% (from 170 to 88 mW/m2) for MnO2‐based cathode MFC. However, in RGO/MnO2 nanocomposite cathode MFC, the percent of reduction in power density was 26.4% (from 170 to 125 mW/m2). It can be concluded that RGO nanosheets loaded with Pt nanoparticles is a starting point for finding an alternative economic and effective cathode.