Alcohol dehydrogenase as bioanode for methanol and ethanol oxidation in a microfluidic fuel cell

In this work, an enzymatic bioanode was developed using functionalized carbon nanofibers for the immobilization of alcohol dehydrogenase enzyme, using Nafion, tetrabutylammonium bromide and glutaraldehyde onto Toray carbon paper. Two alcoholic fuels, methanol (MeOH) and ethanol (EtOH) were used to demonstrate the oxidation versatility of the electrode created as well as being able to convert energy from these fuels using an air-breathing microfluidic device. Commercial Pt/C (30% E-TEK) onto carbon nanofoam (Marketech Inc) was using as inorganic cathode. Carbon nanofibers were previously treated with nitric acid to produce oxygen-containing functional groups in order to facilitate the enzyme immobilization. A phosphates buffer solution pH 8.86 was used as electrolyte. The use of ethanol as fuel shows a better performance obtaining 8.643mAcm⁻² and 0.847 V as current density and open circuit voltage respectively, compared to that use methanol as fuel (2.655 mAcm⁻² and 0.567V). (paper)