Role of Lattice Oxygen and Lewis Acid on Ethanol Oxidation over OMS-2 Catalyst

Ethanol-gasoline fuel vehicles result in a statistically significant increase in emissions of ethanol, although they are environmentally friendly due to their lower levels of carbon oxide and hydrocarbon emissions. This work focused on catalytic oxidation of ethanol on octahedral molecular sieve (OMS-2) catalyst, which was synthesized using refluxing method. The catalyst demonstrated great reactivity with acetaldehyde as the major intermediate. Small amounts of formaldehyde were detected while little acetic acid was observed in the presence of oxygen. Results suggested that ethanol adsorption occurred through the breakage of O-H bond forming ethoxide species on Lewis acid sites of the catalyst and OMS-2 could partially oxidize adsorbed ethanol to acetaldehyde and formaldehyde from the consumption of catalyst lattice oxygen in the absence of oxygen flow. Acetaldehyde and formaldehyde formed were directly oxidized to carbon dioxide in the presence of an oxygen flow. The major path of ethanol complete oxidation on OMS-2 catalyst appeared to be the direct oxidation of acetaldehyde to carbon dioxide.