POSITION PAPER ON HYDROGEN ECONOMY
3.3.3
Microbial Fuel Cell (MFC)
A microbial fuel cell (MFC) system is a bioenergy converter that utilises bacteria to generate electricity through a bacterial metabolic pathway. In an MFC, bacteria are put in an oxygen- free anolyte compartment together with a suitable carbon source, while the catholyte acts as an electron sink. The high electronegativity at the cathode relative to the anode attracts the bacteria in the anode compartment to transfer electrons outside their cell and pass it to the anode electrode, which acts as an electron acceptor. These bacteria are known as exoelectrogens and could transfer electrons to an anode electrode via direct electron transfer and mediated electron transfer. When oxygen and other anaerobic electron acceptors exist in the anolyte, electricity generation in the MFCs will be impacted. Further studies on the optimisation of the MFC configuration is required to lower the overpotential of large scale MFCs. Preferred materials ranging from carbon to metal, are used to modify and fabricate electrodes to improve power generation. Another challenge is the comparatively lower power production compared to the precious metal abiotic cathodes such as Pt. Useful by-products conjugated with concurrent waste removal and bioelectricity production of biocathodes are promising and worth being further explored as well.
Figure 46: Schematics of a Microbial Fuel Cells
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