Stéphane Loridant

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...

TL;DR: The oxygen storage capacity (OSC) of the mixed oxide systems is more than that of pure CeO(2) and is system dependent, and the exact structural features of these crystals as determined by digital diffraction analysis of HREM experimental images reveal that the CeO-2 is mainly in cubic fluorite geometry.

TL;DR: In this paper, Raman mappings were achieved on this type of samples especially to look for traces of Co3O4 that can be present as additional phase and not detect by XRD.

TL;DR: A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures and exploited to enhance the catalytic activity of Pt/CeO2 -based exhaust gas catalysts.

TL;DR: In this paper, the microstructure evolution of ceria-based mixed oxides CeO2−MO2 (M = Si4+, Ti4+, and Zr4+) after thermal treatments in the temperature range of 773−1073 K were investigated by X-ray diffraction (XRD), Raman spectroscopy, Xray photoelectron spectrograph (XPS), and other techniques.