In situ diffuse reflectance FT-IR studies of TiO2 and Pt/TiO2 in photo-oxidation of benzene and ethylene

In situ diffuse reflectance FT-IR measurements were carried out to investigate the formation and decomposition behavior of by-product compounds on TiO2 and Pt/TiO2 catalyst surfaces during the photo-oxidation of benzene and ethylene. In the benzene photo-oxidation ([benzene] = 100 ppm) without water vapor, TiO2 catalyst was readily covered with oxygen-containing by-product compounds, which were decomposed by, photoirradiation in the presence of water vapor ([H2O] = 0.17%) with an induction period. Pt deposition slightly increased the rate for their decomposition. In the ethylene photo-oxidation ([ethylene] = 400 ppm) without water vapor, oxygen-containing by-product compounds were also formed, which were readily decomposed by photoirradiation in the presence of water vapor without induction period. Pt deposition on TiO2 surface had no significant effect on the photo-oxidation processes.