Catalytic oxidation of CO over Pt/TiO2 with low Pt loading: The effect of H2O and SO2

Anatase TiO 2 loaded with 0.1wt.% Pt catalyst (0.1Pt/TiO 2 -A) was prepared via the impregnation method, and its CO catalytic oxidation activity was investigated. Noteworthy, introduction of H 2 O into the reaction atmosphere apparently facilitated the catalytic oxidation of CO. Besides, introduction of SO 2 inhibited the catalytic oxidation of CO. In presence of H 2 O and SO 2 , 0.1Pt/TiO 2 -A showed outstanding catalytic stability, and X-ray photoelectron spectroscopy (XPS) and thermogravimetric (TG) characterizations suggested that the amount of sulfate species deposited on the 0.1Pt/TiO 2 -A treated at 230 °C did not increase with time extension, which might be an important reason for the high sulfur resistance of 0.1Pt/TiO 2 -A. XPS results also demonstrated that the dissociation of H 2 O led to considerably increase of hydroxyl groups over the catalyst surface. H 2 18 O isotope-labeling experiments unambiguously showed that C 16 O 18 O was the main product accounting for 88.9%, revealing that the other oxygen atom in the product CO 2 was mostly from H 2 O. Consequently, based on previous researches and our experimental results, the mechanism of H 2 O promoting CO oxidation on 0.1Pt/TiO 2 -A catalyst was proposed.