On the role of gold nanoparticles in the selective photooxidation of 2-propanol over Au/TiO2

Abstract

The gas-phase photooxidation of 2-propanol over Au/TiO₂ and TiO₂ was studied by infrared spectroscopy and online mass spectrometry to gain insight into the mechanism and the role of gold. The presence of O₂ was found to be essential for the formation of acetone under UV irradiation at room temperature. In the presence of gold nanoparticles the rate of acetone formation was increased compared to pure TiO₂. Baseline bending in the ATR-IR spectra was used as a tool to monitor the accumulation of excess electrons. Electron accumulation was absent in the presence of gold and O₂ suggesting that the gold nanoparticles act as co-catalysts enhancing the rate of electron transfer from TiO₂ to adsorbed O₂ species.