Adsorption of CO and NO on Ceria- and Pt-Supported TiO2: In Situ FTIR Study

Pt/TiO2, Ce/TiO2 and binary system PtCe/TiO2 catalysts were prepared by impregnation method and the structural properties of these catalysts were investigated by means of XRD, CO-TPD and UV-vis diffuse reflectance spectroscopy. As investigated by XRD, the composition of the prepared samples anatase and rutile phases with higher amount of anatase phase and its particle size was in the range of 19 22 nm. The band gap also decreased from 3.1 to 2.85 after addition of metal to TiO2. The adsorption and interaction properties of NO and/or CO gases were monitored using an in situ FTIR technique. The intensity and position of the infrared peaks were strongly dependent on the composition of the catalyst. In presence of Pt, the main oxidative reductive products of (NO + CO) are CO2 and NCO complex. The formation of NCO depends on not only the presence of platinum in the catalyst but also the presence of Lewis acid sites which is Ti in this study. However, the interaction between NO and CO gases increased in presence of CeO2. The optimum Ce content in PtCe/TiO2 was 0.1% (Ce/TiO2) at which the maximum peak intensity was observed for NCO and CO2.