Ethanol stripping in alkaline medium: A DEMS study

In this study, the adsorption of ethanol on platinum in alkaline medium is investigated by stripping voltammetry in combination with differential electrochemical mass spectrometry (DEMS). It is shown that the amount of adsorbed ethanol depends on the adsorption potential. Adsorbed ethanol can be oxidized to carbon dioxide in two different potential regions: one below 0.9 V vs. RHE and the other above 0.9 V vs. RHE. Furthermore, adsorbed ethanol can be reduced to methane below 0.2 V vs. RHE when the stripping voltammogram is started in cathodic direction from the adsorption potential. The number of electrons transferred per molecule of carbon dioxide evolved is calculated and found to be two in the potential region below 0.9 V vs. RHE, independent of the adsorption potential. A larger number of electrons is found in the potential region above 0.9 V vs. RHE. Based on the findings, a preliminary reaction scheme is presented.