| Abstract: | The photocatalytic oxidation of ethanol over TiO2 nanotubes (NTs) was investigated by in situ attenuated total reflection using Fourier transform infrared spectroscopy (ATR-FTIR) and ultraviolet (UV)-visible spectroscopy. In the ATR-FTIR study, the TiO2 NTs were spread in a ZnSe crystal trough that was used as the reactor. The evolution of the reaction under UV irradiation was investigated by in situ monitoring of changes in the species at the surface of the TiO2 NTs. Ethanol adsorbed on the TiO2 NTs surface, forming alkoxide and hydroxide groups, which were then attacked by ?OH, with the formation of a vinyl alcohol intermediate that was finally transformed to acetic acid. In addition, the species changes in the reaction solution were also investigated by in situ UV-visible spectroscopy using a small volume flow-through cell. The UV-visible data further confirmed the oxidation mechanism of ethanol on TiO2 NTs elucidated by ATR-FTIR data. |
