Gas-phase oxidation of alcohols with dioxygen over 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°C, while the complete conversion of the alcohols is achieved at 200–300°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