Highly dispersed silica-supported ceria–zirconia nanocomposites: Preparation and characterization (original) (raw)

Surfaces and Interfaces, 2016

Abstract

Abstract Ternary CeO 2 –ZrO 2 /SiO 2 nanocomposite oxides were synthesized by a liquid-phase method and subjected to thermal treatment at 550 °C. The physicochemical characterization of the obtained nanosized systems was carried out by various techniques, namely: X-ray diffraction (XRD), nitrogen adsorption–desorption, Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). The XRD measurements revealed the presence of cubic phase Zr 0.4 Ce 0.6 O 2 in CZS1 (CeO 2 :ZrO 2 :SiO 2 = 3:10:87) and CZS2 (CeO 2 :ZrO 2 :SiO 2 = 10:10:80) samples. The crystallinity of this phase slightly increased with increasing ceria content in nanocomposites. Raman spectra indicated the presence of oxygen vacancies in the case of CZS2 and an absence displacement of oxygen ions from their normal lattice positions in both of the samples. XPS data indicated a significant quantity of Ce 3+ ions present in the composites, which is greater in the CZS2 composite. In the case of CZS systems the TEM–HRTEM results showed well-dispersed nanosized Zr–Ce–oxides over the surface of amorphous SiO 2 . All the characterization techniques revealed that silica does not form any compounds with the dispersed Zr–Ce-oxides. The prepared materials were tested in catalytic reaction of CO oxidation in the presence of H 2 and it was shown that CZS2 system had better performance than CZS1 one.

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