In this work, we investigate the effects of ethanol concentration on the yields Of CO2, acetic acid and acetaldehyde as electrooxidation products. FTIR spectra show that the main oxidation product at low ethanol concentrations is acetic acid, CO2 being produced to a minor extent. For concentrated ethanol solutions, the pathway producing acetaldehyde becomes dominant. The CO2 production passes through a maximum at 0.025 M C2H5OH and then decreases. The intensity of the IR absorption band for COad, which is one of the adsorbed intermediates, is practically independent of ethanol concentration. (c) 2005 Elsevier B.V. All rights reserved.