Reactivity of acetaldehyde at platinum and rhodium in acidic media.: A DEMS study

The electrochemical behaviour of acetaldehyde at platinum and rhodium electrodes in acid solutions was studied applying differential electrochemical mass spectrometry (DEMS). In an acetaldehyde-containing solution, CO2 was the sole electrooxidation product detected at both electrodes, whereas only methane was recorded in the hydrogen region. The production of acetic acid was indirectly established at platinum from DEMS. Residues were studied through the design of flow cell experiments. As for the acetaldehyde-containing solution, the adsorbates produce CO2 and methane during the oxidation and reduction processes, respectively. However, ethane was also observed at platinum during the cathodic stripping of the adspecies. The yield of these substances depends on the adsorption potential These results suggest that the fragmentation of acetaldehyde occurs during adsorption and reduction reactions, and the extent of the C-C bond scission is influenced by the E-ad and the nature of the electrode, being favoured at rhodium. (C) 2002 Elsevier Science Ltd. All rights reserved.