Considering Species Potentials in a Methanol-Oxygen BFC

Consider the methanol-oxygen fuel cell, in which methanol is oxidized to carbon dioxide and oxygen is reduced to water, for the overall reaction (Equation 9.14)  

The theoretical maximum potential of this electrochemical cell is AFeq = oxygen - 

These potentials are those at the electrode current collector surfaces. Considering this, a disadvantage to MET in comparison to DET becomes apparent. In DET, the overpotential at the anode would be relative to the redox potential of the enzyme active site. In MET, the overpotential is relative to the mediator redox potential. For an anode, we may write an equation similar to Equation 9.6 (Equation 9.17)  

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