Dimethoxymethane (DMM) electrooxidation on polycrystalline platinum electrode in acid media

The electrooxidation of dimethoxymethane (DMM) was studied on polycrystalline platinum electrode. Cyclic voltammetry has shown that the behaviour of DMM electrooxidation depends on scan rate, DMM concentration and the nature of anion of the supporting electrolyte. At a low scan rate or at a high DMM concentration, the electrode is strongly poisoned during DMM electrooxidation, which is an anion-sensitive reaction. Using electrochemical and in situ IR experiments, a multistep mechanism was proposed with DMM adsorption as the first and rate-determining step. At a low potential range, adsorbed CO is slowly formed. COads inhibits the DMM electrooxidation until it is full oxidized to CO2. Conversely, for lower adsorbed CO coverage, oxidation starts earlier and CO2 formation is observed. In situ infrared reflectance spectroscopy experiments were carried out to identify these adsorbed species intermediates and reaction products of DMM adsorption and oxidation. In addition to adsorbed COL (linearly bonded CO), adsorbed HCO, CH3O species and CO2 were detected suggesting a complex mechanism of the electrooxidation of DMM, with parallel paths involving methanol and formaldehyde electrooxidation.