Journal ArticleDOI
Characterization of ceria-coated alumina carrier
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TLDR
In this paper, it was shown that different types of cerium oxide species are formed on the surface depending on the amount of CeO2 and temperature of calcination of the samples.Abstract:
CeO2–Al2O3 mixed oxides with different CeO2 loading (in the range of 0.5–12 wt.%) were prepared by wetness impregnation of alumina with aqueous solution of di-ammonium hexanitrate cerate (NH4)2[Ce(NO3)6]. The samples after calcination at 773 and 1073 K were characterized by different techniques, using X-ray diffraction (XRD), UV–VIS diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR). It is shown that different types of cerium oxide species are formed on the surface depending on the amount of CeO2 and temperature of calcination of the samples. XRD showed the formation of nanocrystallites of ceria on alumina surface when the amount of CeO2 is higher than 6 wt.%; at lower concentrations ceria was found to be amorphous. The ceria loading lower than 6 wt.% stabilizes the textural properties of alumina. At loading of 1 wt.% of CeO2 XPS spectra reveals the presence of a strong interaction between ceria and alumina leading to a formation of superficial CeAlO3-like phase. TPR results show that well dispersed CeO2 particles present on the surface of alumina form CeAlO3 at temperature of reduction in the range of 873–993 K, while for the reduction of CeO2 crystallites, a higher temperature of reduction of 1190 K is needed.read more
Citations
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Journal ArticleDOI
Al2O3-CeO2 Oxides: Synthesis, Characterization and Evaluation as Catalytic Supports in Benzene Combustion. Surface Ceria Effects
TL;DR: In this paper, surface ceria dispersion degree (surface ceria/total reduced ceria) was determined to be 100% for samples with 2 and 5 wt.% CeO2, with a slight decrease to ca. 90'% and 75'% respectively, and a lower value of 41'% for the sample with 50 wt.'s CeO 2.
Journal ArticleDOI
Preparation and properties of nanophase (Ce, Zr, Pr)O2-doped alumina coating on cordierite ceramic honeycomb for three-way catalysts
Jiuying Tian,Jusheng Lu +1 more
TL;DR: In this paper, the effects of preparation methods on the crystal phase, texture, oxygen storage capacity (OSC), reducibility, surface morphology and thermal stability of coatings were investigated by X-ray diffraction (XRD), the Brunauer Emmet Teller (BET) method, the oxygen pulsing technique, H2-temperature-programmed reduction (H2-TPR) and scanning electron microscopy (SEM).
DissertationDOI
Desenvolvimento de catalisadores de cobalto suportados em matrizes de Al2O3,CeO2, e ZrO2 para produção de hidrogênio a partir da reforma a vapor e oxidativa do etanol
Journal ArticleDOI
Experimental study on the deactivating effect of KNO 3 , KCl, and K 2 SO 4 on nanosized ceria/titania SCR catalyst
TL;DR: In this paper, the authors showed that the deactivation of CeO2/TiO2 is attributed to the changes in the structural and chemical state of ceria and the degradation of surface acidity.
Patent
Alumina supported type cerium oxide powder material preparation method
TL;DR: In this paper, an alumina supported type cerium oxide powder material preparation method is described, which comprises: chemical vapor deposition method is adopted, a cerium metal organic precursor is effectively decomposed in an oxygen atmosphere and in a temperature range of 500-700 DEG C, and CeO nano particles are generated and uniformly dispersed on the support alumina.
References
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Journal ArticleDOI
Catalytic Properties of Ceria and CeO2-Containing Materials
TL;DR: A survey of the use of cerium oxide and CeO2-containing materials as oxidation and reduction catalysts is presented in this paper, with a special focus on catalytic interaction with small molecules such as hydrogen, carbon monoxide, oxygen, and nitric oxide.
Journal ArticleDOI
Ceria in automotive exhaust catalysts: I. Oxygen storage
H.C. Yao,Y.F. Yu Yao +1 more
TL;DR: In this article, the authors measured the oxygen removal at various temperatures using TPR traces of unsupported or alumina-supported ceria and showed that the reduction of surface capping oxygen and bulk oxygen anions is associated with reduction of the shared oxygen anion at the interface.
Book
X-Ray Diffraction in Crystals, Imperfect Crystals, and Amorphous Bodies
TL;DR: In the formalism of Newman-Penrose, a family of exact solutions of the Einsteirr-Maxwell equations of the type of Bertotti-Robinson is obtained with a cosmological term belonging to the degenerate type D in the algebraic classification of Petrov.