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
Synthesis and characterization of Fe/CeO2 catalysts: Epoxidation of cyclohexene
A. Satyanarayana Reddy,Chien-Yen Chen,Chien-Cheng Chen,Shu-Hua Chien,Chin-Jung Lin,Kao Hung Lin,Chih Lei Chen,Shiuan Chih Chang +7 more
TL;DR: In this article, the performance of the catalysts of varying composition, and catalytic activity and product selectivity were found to strongly depend on catalyst composition, acidity and reducibility.
Journal ArticleDOI
Enhancement of the low-temperature activity of Ce/TiO2 catalyst by Sm modification for selective catalytic reduction of NOx with NH3
Peng Sun,Rui-tang Guo,Shu-ming Liu,Shu-xian Wang,Wei-guo Pan,Ming-yuan Li,Shuai-wei Liu,Jian Liu,Xiao Sun +8 more
TL;DR: CeSmOx mixed oxide catalysts supported on TiO 2 prepared by coprecipitation method were used for selective catalytic reduction of NOx with NH 3, and the results showed that the addition of Sm could effectively enhance the low-temperature SCR activity and SO 2 /H 2 O resistance of Ce/TiO 2 catalyst, and the appropriate mole ratio of Sm to Ce was 0.3.
Journal ArticleDOI
Partial oxidation and autothermal reforming of methane on Pd/CeO2–Al2O3 catalysts
L. S. F. Feio,Carla E. Hori,Lisiane V. Mattos,Daniela Zanchet,Fabio B. Noronha,José Maria C. Bueno +5 more
TL;DR: The surface properties and catalytic behavior of Pd/Al 2 O 3 catalysts in partial oxidation of methane and autothermal reforming of methane were investigated in this article, where an increase on ceria's apparent crystallite sizes with the increase of CeO 2 loadings and with the rise of the calcination temperatures of the supports from 500 to 900°C.
Journal ArticleDOI
Synergistic effect between ceria and tungsten oxide on WO3–CeO2–TiO2 catalysts for NH3-SCR reaction
TL;DR: WO3-CeO2-TiO2 catalysts for NO (nitrogen monoxide) reduction by ammonia were prepared by a sol-gel method as discussed by the authors, and the catalysts were characterized by BET, XRD, Raman, NH3/NO adsorption and H2-TPR to investigate the relationships among the catalyst composition, structure, redox property, acidity and deNOx activity.
Journal ArticleDOI
Comparative synthesis and physicochemical characterization of CeO2 nanopowder via redox reaction, precipitation and sol–gel methods used for total oxidation of toluene
TL;DR: Nanostructured CeO2 physicochemical properties were assessed by XRD, FESEM, BET, TPR-H2, TPD-CO2 and FTIR analyses as mentioned in this paper.
References
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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.