Structural Characterization of CeO2−TiO2 and V2O5/CeO2−TiO2 Catalysts by Raman and XPS Techniques

Abstract

Structural characteristics of ceria−titania and vanadia/ceria−titania mixed oxides have been investigated using X-ray powder diffraction (XRD), Raman spectroscopy (RS), and X-ray photoelectron spectroscopy (XPS) techniques. The (1:1 mole ratio) mixed oxide was obtained by a coprecipitation method, and a nominal 5 wt % V2O5 was deposited over its surface by a wet impregnation technique. Both of the materials were then subjected to thermal treatments from 773 to 1073 K and were characterized by the above-mentioned techniques. The XRD results suggest that the CeO2−TiO2 mixed oxide calcined at 773 K primarily consists of poorly crystalline CeO2 and TiO2-anatase phases and that a better crystallization of these oxides occurs with increasing calcination temperature. The “a” cell-parameter values suggest some incorporation of titanium into the ceria lattice. Impregnation of vanadia on ceria−titania enhances the crystallization of CeO2 and TiO2 oxides. However, no crystalline V2O5 could be observed from XRD and R...