Textural and phase stability of CexZr1−xO2 mixed oxides under high temperature oxidising conditions

Colón, G.; Valdivieso, Françoise; Pijolat, Michèle; Baker, Richard T.; Calvino, José J.; Bernal, S.

doi:10.1016/s0920-5861(98)00509-4

Cited by 105 publications

(70 citation statements)

References 9 publications

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“…According to previous literature, the cubic fluorite structure by and large exhibits only three electron diffraction rings which correspond to the interplanar spacings of ca. 3.1 (111), 2.7 (200), and 1.9 (220)Å [50,51]. This feature is quite prominent in the prepared materials which are once again in compliance with the formation of cubic fluorite pattern of the materials.…”

Section: Resultssupporting

confidence: 70%

Enhanced Catalytic Activity of Supported Gold Catalysts for Oxidation of Noxious Environmental Pollutant CO

Saikia

Miah

Malakar

et al. 2015

Indian Journal of Materials Science

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Noble metal nanomaterials have attracted mounting research attention for applications in diverse fields of catalysis, biology, and nanotechnology. In the present study, we have undertaken a detailed investigation on synthesis, characterization, and catalytic activity studies for CO oxidation by nanogold catalysts supported over CeO 2 and CeO 2 -ZrO 2 (1 : 1 mole ratio). The support systems were prepared by modified, simple precipitation technique and the Au supported samples were synthesized using depositionprecipitation with urea method. The physicochemical characterization was performed by XRD, ICP-AES, BET surface area, FT-IR, UV-Vis DRS, Raman Spectroscopy, TEM, and XPS techniques. Au/CeO 2 catalyst showed more than 80% CO conversions at 30 ∘ C, whereas Au/CeO 2 -ZrO 2 exhibited ∼100% CO conversion at that temperature. The catalytic performance of Au catalysts is highly dependent on the nature of the support.

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Section: Resultssupporting

confidence: 70%

Enhanced Catalytic Activity of Supported Gold Catalysts for Oxidation of Noxious Environmental Pollutant CO

Saikia

Miah

Malakar

et al. 2015

Indian Journal of Materials Science

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“…The inter planar spacing values of 3.0, 2.6, and 3.0 Å were measured from the DDP and could be respectively assigned to (111), (200), and (1-1-1) family planes of the cubic structure. As per previous literature reports [37,38], the electron diffraction pattern of fluorite cubic structure is characterized by the presence of first three electron diffraction rings which correspond to the inter planar spacings of ca. 3.1 (111), 2.7 (200) and 1.9 (220) Å.…”

Section: Mwsupporting

confidence: 72%

Synthesis of Nanosized Ceria-Zirconia Solid Solutions by a Rapid Microwave-Assisted Combustion Method

Reddy¹,

Reddy²,

Reddy³

et al. 2009

TOPCJ

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By adopting a simple cost effective microwave-assisted synthesis methodology, nanosized ceria-zirconia solid solution (MW) has been prepared. For comparison purpose, ceria-zirconia solid solution with the same composition was also synthesized by a coprecipitation method (CP) and calcined at 773 K. Both the samples were examined by different characterization techniques namely, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, BET surface area and other methods, and evaluated for CO oxidation activity. XRD studies revealed formation of monophasic Ce 0.5 Zr 0.5 O 2 solid solution in the MW sample and Ce 0.75 Zr 0.25 O 2 solid solution in the CP sample. TEM studies showed the presence of nanometre sized particles with broad particle size distribution in the sample prepared by microwave method. Raman spectroscopy and oxygen storage capacity measurements suggested the presence of more oxygen vacancies and lattice defects in the MW sample. XPS studies indicated a high reducibility and surface enrichment of Ce 3+ ions in the MW sample. Higher CO oxidation activity and lower light off temperature was observed for the microwave synthesized sample in comparison to that of coprecipitated sample.

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“…The corresponding DDPs are also shown as insets in figure 9. Analysis of the spots labeled 1, 2, 3 and 4 (top right inset) revealed the typical diffraction pattern of the anatase-TiO 2 , with interplanar spacings of 3.42, 2.66, 3.54 and 2.3 Å corresponding to (101), (110), (01-1) and (-11-2) planes, respectively [100]. The other DDP (left inset) revealed the typical diffraction pattern of CeO 2 phase.…”

Section: High-resolution Transmission Electron Microscopy Studiesmentioning

confidence: 99%

Nanosized CeO2–SiO2, CeO2–TiO2, and CeO2–ZrO2 Mixed Oxides: Influence of Supporting Oxide on Thermal Stability and Oxygen Storage Properties of Ceria

2005

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The influence of SiO 2 , TiO 2 , and ZrO 2 on the structural and redox properties of CeO 2 were systematically investigated by various techniques namely, X-ray diffraction (XRD), Raman spectroscopy (RS), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HREM), BET surface area, and thermogravimetry methods. The effect of supporting oxides on the crystal modification of ceria was also mainly focused. The investigated oxides were obtained by soft chemical routes with ultrahigh dilute solutions and were subjected to thermal treatments from 773 to 1073 K. The XRD results suggest that the CeO 2 -SiO 2 sample primarily consists of nanocrystalline CeO 2 on the amorphous SiO 2 surface. Both crystalline CeO 2 and TiO 2 -anatase phases were noted in the case of CeO 2 -TiO 2 sample. Formation of cubic Ce 0.75 Zr 0.25 O 2 and Ce 0.6 Zr 0.4 O 2 (at 1073 K) were observed in the case of CeO 2 -ZrO 2 sample. The cell 'a' parameter estimations revealed an expansion of the ceria lattice in the case of CeO 2 -TiO 2 , while a contraction is noted in the case of CeO 2 -ZrO 2 . The DRS studies suggest that the supporting oxides significantly influence the band gap energy of CeO 2 . Raman measurements disclose the presence of oxygen vacancies, lattice defects, and displacement of oxide ions from their normal lattice positions in the case of CeO 2 -TiO 2 and CeO 2 -ZrO 2 samples. The XPS studies revealed the presence of silica, titania, and zirconia in their highest oxidation states, Si(IV), Ti(IV), and Zr(IV) at the surface of the materials. Cerium is present in both Ce 4+ and Ce 3+ oxidation states. The HREM results reveal well-dispersed CeO 2 nanocrystals over the amorphous SiO 2 matrix in the case of CeO 2 -SiO 2 , isolated CeO 2 and TiO 2 (A) nanocrystals and some overlapping regions in the case of CeO 2 -TiO 2 , and nanosized CeO 2 and Ce-Zr oxides in the case of CeO 2 -ZrO 2 sample. 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. The oxygen storage capacity (OSC) as determined by thermogravimetry reveals that the OSC of mixed oxides is more than that of pure CeO 2 and the CeO 2 -ZrO 2 exhibits highest OSC.

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Textural and phase stability of CexZr1−xO2 mixed oxides under high temperature oxidising conditions

Cited by 105 publications

References 9 publications

Enhanced Catalytic Activity of Supported Gold Catalysts for Oxidation of Noxious Environmental Pollutant CO

Enhanced Catalytic Activity of Supported Gold Catalysts for Oxidation of Noxious Environmental Pollutant CO

Synthesis of Nanosized Ceria-Zirconia Solid Solutions by a Rapid Microwave-Assisted Combustion Method

Nanosized CeO2–SiO2, CeO2–TiO2, and CeO2–ZrO2 Mixed Oxides: Influence of Supporting Oxide on Thermal Stability and Oxygen Storage Properties of Ceria

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