Development of Electro-Catalysts for the Alcohol Oxidation in Anion Exchange Membrane Direct Alcohol Fuel Cells

The oxidation of ethanol and ethylene glycol at platinum as model catalyst was investigated in potassium hydroxide solution. Experiments comprised the investigation of formed adsorbates by stripping voltammetry of pre-adsorbed alcohols and the investigation of the bulk oxidation as function of the alcohol bulk concentration by cyclic voltammetry and chronoamperometry. For all measurements online mass spectrometry was used to detect the volatile reaction products. For both alcohols it was found that during stripping experiments only the C1 products are formed. For the bulk oxidation of ethanol the CO2 current efficiency rapidly decreases with increasing ethanol concentration showing hardly any CO2 formation at technical relevant concentrations. Although CO2 current efficiencies also dropped for the ethylene glycol oxidation with increasing concentration,the effect was much less pronounced. CO2 formation was thus also observed at technical relevant ethylene glycol concentrations even after longer times under potentiostatic conditions.