Gas-Phase Oxidation of Alcohols with Dioxygen over an Au/TiO2 Catalyst: The Role of Reactive Oxygen Species

The activity of the (3% Au)/TiO2 catalyst with an average gold particle size of 3.6 +/- 1.0 nm in the gas-phase oxidation of lower aliphatic alcohols (ethanol, propanol, isopropanol, and butanol) into the corresponding carbonyl compounds (acetaldehyde, propanal, acetone, and butanal) has been studied. A two-peak profile of the activity of the catalyst as a function of temperature has been observed in all of the reactions. The first peak falls within the temperature range from 120 to 130 degrees C, while the complete conversion of the alcohols is achieved at 200-300 degrees C. It is hypothesized that the low-temperature activity is due to the generation of a thermally unstable reactive oxygen species on the catalyst surface.