Influence of molar ratio and calcination temperature on the properties of TixSn1 − xO2 supporting copper oxide for CO oxidation.

Ti x Sn 1 − x O 2 mixed oxides were synthesized by the coprecipitation method. CuO/Ti x Sn 1 − x O 2 catalysts were then prepared by wetness impregnation of the mixed oxides with Cu(NO 3 ) 2 . These catalysts were characterized using X-ray diffraction (XRD), laser Raman spectroscopy (LRS), H 2 -temperature-programmed reduction (TPR), O 2 -temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and in situ Fourier transform infrared (FT-IR) techniques. The activities of the catalysts during CO oxidation were evaluated. The following observations were made: (1) CuO species can be highly dispersed on the Ti x Sn 1 − x O 2 supports, such that several surface Cu + ions and oxygen vacancies are formed. (2) Among the prepared catalysts, the 5CuO/Ti 0.75 Sn 0.25 O 2 -600 °C catalyst exhibits the highest reducing property, which arises from the difference in electronegativity between Ti and Sn. (3) The CO species can adsorb on Cu + and O 2 on the oxygen vacancy, which forms O 2 − species. The in situ FT-IR results show that the Cu + –(CO) 2 species and O 2 − adsorbed on the catalyst play a key role in CO oxidation. (4) The resistance of the catalysts to H 2 O is related to the Brunauer–Emmett–Teller (BET) surface area and the H 2 O adsorption on the catalyst surface. Furthermore, a possible reaction mechanism is tentatively proposed to understand this reaction. [ABSTRACT FROM AUTHOR]