MnO2-graphene hybrid as an alternative cathodic catalyst to platinum in microbial fuel cells

► MnO2-graphene nanosheet (MnO2/GNS) hybrid is prepared under microwave irradiation. ► The electrode modified by MnO2/GNS exhibits high catalytic activity for ORR. ► Microbial fuel cells with MnO2/GNS generates a maximum power density of 2083 mW m−2.