In situ ATR-SEIRAS study of electrooxidation of dimethyl ether on a Pt electrode in acid solutions

The electrooxidation of dimethyl ether (DME) was studied on a Pt film electrode in HClO 4 solution using surface enhanced infrared absorption spectroscopy (SEIRAS) and cyclic voltammetry. (CH 2OCH 3) ad and η 2(O, C)-H 2CO are inferred as the adsorbed intermediates resulting from the dissociative adsorption of DME in the hydrogen adsorption region. Adsorbed CO was also found, with coverages increasing rapidly upon DME adsorption, probably due to the further dissociation of (CH 2OCH 3) ad and η 2(O, C)-H 2CO. In the main oxidation region no adsorbed species, excluding CO, were found. However, for low DME concentration (0.025 M), vibration bands associated with adsorbed CH 3COO or CH 3OCOO were observed between 0.3 and 0.95 V. These results lead to the conclusion that the reaction products could depend on the concentration of the fuel. Additional discussion of the reaction mechanism is also presented. © 2005 Elsevier B.V. All rights reserved