Graphene/Fe₃ O₄ Nanocomposites as Efficient Anodes to Boost the Lifetime and Current Output of Microbial Fuel Cells

The enhancement of microbial activity and electrocatalysis through the design of new anode materials is essential to develop microbial fuel cells (MFCs) with longer lifetimes and higher output. In this research, a novel anode material, graphene/Fe₃ O₄ (G/Fe₃ O₄ ) composite, has been designed for Shewanella-inoculated MFCs. Because the Shewanella species could bind to Fe₃ O₄ with high affinity and their growth could be supported by Fe₃ O₄ , the bacterial cells attached quickly onto the anode surface and their long-term activity improved. As a result, MFCs with reduced startup time and improved stability were obtained. Additionally, the introduction of graphene not only provided a large surface area for bacterial attachment, but also offered high electrical conductivity to facilitate extracellular electron transfer (EET). The results showed that the current and power densities of a G/Fe₃ O₄ anode were much higher than those of each individual component as an anode.