Generation of Active Sites for CO Photooxidation on TiO2by Platinum Deposition

Photocatalytic oxidation of CO to CO 2 was carried out with TiO 2 and Pt/TiO 2 catalysts at room temperature to investigate the effect of Pt deposition. The rate for CO photooxidation by Pt/TiO 2 was higher than that by TiO 2 . The reaction rate increased with incident light intensity to the power of 0.7 for Pt/TiO 2 and 0.5 for TiO 2 . The dependency of reaction rate on the concentration of CO and water vapor was explained in terms of Langmuir−Hinshelwood mechanism, where CO was more efficiently adsorbed on Pt sites compared with TiO 2 . On the basis of diffuse reflectance FTIR spectroscopic studies and CO photodesorption measurements, Pt on TiO 2 acted as the active sites on which CO was chemically adsorbed and oxidized to CO 2 on photoirradiation in the presence of O 2 .