Fe3O4 nanospheres decorated reduced graphene oxide as anode to promote extracellular electron transfer efficiency and power density in microbial fuel cells

Abstract

Fe3O4 nanospheres decorated reduced graphene oxide nanocomposites (Fe3O4-NS/rGO) with various Fe3O4 content are developed via a facile one-pot solvothermal synthetic procedure and applied for anode bio-electrocatalysts of microbial fuel cells (MFCs). Addition of reduced graphene oxide (rGO) nanosheets can effectively overcome the poor electron transportation efficiency of Fe3O4. Additionally, the bioaffinity of Fe3O4-NS/rGO anodes is promoted by incorporating with Fe3O4 nanospheres (Fe3O4-NS). These merits collectively result in the accelerated extracellular electron transfer (EET) efficiency and remarkable power density production on Fe3O4-NS/rGO bioanodes for MFCs. The maximum power outputs of MFCs with all Fe3O4-NS/rGO anodes are superior to that of carbon paper (CP), Fe3O4-NS and rGO anodes under the same regimes and conditions. Especially, the Fe3O4-NS/rGO (1.5:1) anode as the optimized ratio yields the maximum power density 1837.4 mW m−2 at the scan rate of 0.001 V s−1, this is much higher compared to other anodes. The characters of predominant power density output and extraordinary nanospheres morphology combining with the facile fabrication of nanocomposites electrocatalysts together suggest positive implication towards the practical implementation of high performance MFCs.