Effect of ZrO2 content on textural and structural properties of CeO2–ZrO2 solid solutions made by citrate complexation route

Kašpar, Jan; Fornasiero, Paolo; Balducci, Gabriele; Monte, R. Di; Hickey, Neal; Sergo, Valter

doi:10.1016/s0020-1693(03)00034-3

Cited by 158 publications

(112 citation statements)

References 47 publications

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“…X-ray diffraction (XRD) data was collected using a Rigaku Geigerflex diffractometer with CuKα radiation (λ = 1.5405 Å). The average crystallite sizes of the oxidized samples were determined using the width of (220) diffraction peak and the Debye-Scherrer equation [38].…”

Section: Samplesmentioning

confidence: 99%

Oxidation enthalpies for reduction of ceria surfaces

et al. 2007

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The thermodynamic properties of surface ceria were investigated through equilibrium isotherms determined by flow-titration and coulometric-titration measurements on high-surface-area ceria and ceria supported on La-modified alumina (LA). While the surface area of pure ceria was found to be unstable under redox conditions, the extent of reduction at 873 K and a P(O 2 ) of 1.6x10 -26 atm increased with surface area. Because ceria/LA samples were stable, equilibrium isotherms were determined between 873 and 973 K on a 30-wt% ceria sample. Oxidation enthalpies on ceria/LA were found to vary with the extent of reduction, ranging from -500 kJ/mol O 2 at low extents of reduction to near the bulk value of -760 kJ/mol O 2 at higher extents. To determine whether +3 dopants could affect the oxidation enthalpies for ceria, isotherms were measured for Sm +3 -doped ceria (SDC) and Y +3 -doped ceria. These dopants were found to remove the phase transition observed in pure ceria below 973 K but appeared to have minimal effect on the oxidation enthalpies. Implications of these results for catalytic applications of ceria are discussed. AbstractThe thermodynamic properties of surface ceria were investigated through equilibrium isotherms determined by flow-titration and coulometric-titration measurements on high-surfacearea ceria and ceria supported on La-modified alumina (LA). While the surface area of pure ceria was found to be unstable under redox conditions, the extent of reduction at 873 K and a P(O 2 ) of 1.6x10 -26 atm increased with surface area. Because ceria/LA samples were stable, equilibrium isotherms were determined between 873 and 973 K on a 30-wt% ceria sample. Oxidation enthalpies on ceria/LA were found to vary with the extent of reduction, ranging from -500 kJ/mol O 2 at low extents of reduction to near the bulk value of -760 kJ/mol O 2 at higher extents.To determine whether +3 dopants could affect the oxidation enthalpies for ceria, isotherms were measured for Sm +3 -doped ceria (SDC) and Y +3 -doped ceria. These dopants were found to remove the phase transition observed in pure ceria below 973 K but appeared to have minimal effect on the oxidation enthalpies. Implications of these results for catalytic applications of ceria are discussed.

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Section: Samplesmentioning

confidence: 99%

Oxidation enthalpies for reduction of ceria surfaces

et al. 2007

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“…Actually, the thermal stability and the modification of the textural properties have been closely related to the OSC promotion. Besides this, Di Monte et al [1] [13] suggested that the increase of CeO 2 content in Ce X Zr 1-X O 2 mixed oxides produces the increase of BET area and solids with a ceria content superior than that of Ce 0.4 Zr 0.6 O 2 may be are candidates for low to medium temperature catalytic applications, avoiding the phase segregation. On the other hand, Masui et al [14] presented the synthesis of Ce 0.5 Zr 0.5 O 2 employing different experimental procedures and the evolution of a cubic pyrochlore-type structure was detected in some cases.…”

Section: Introductionmentioning

confidence: 99%

Synergy between gold and oxygen vacancies in gold supported on Zr-doped ceria catalysts for the CO oxidation

Laguna

Pérez

Centeno

et al. 2015

Applied Catalysis B: Environmental

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“…These are shown in the supporting information as Figure S1 and Figure S2. Features in the Raman spectra of the materials between 1000 cm -1 and 2000 cm -1 have been ascribed to surface formats and carbonates [35][36]. These peaks become less pronounced as the ZrO 2 content increases.…”

Section: Soot Combustion Activity and Room Temperature Raman Spectramentioning

confidence: 97%

Attempts at an in situ Raman study of ceria/zirconia catalysts in PM combustion

Sullivan

Dulgheru

Atribak

et al. 2011

Applied Catalysis B: Environmental

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Publisher's statementThis is the author's version of a work that was accepted for publication in Applied Catalysis B: Environmental. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Catalysis B: Environmental, 108-109 (1) Ce (x) Zr (1-x) O 2 catalysts with various Ce / Zr contents were studied using Raman spectroscopy under different gaseous atmospheres, at different temperatures and in the presence of a model soot.Catalysts with high concentrations of Zr fluoresced at elevated temperatures making analysis of their spectra impossible. This effect became even more pronounced at higher temperatures. CeO 2 and solid solutions with relatively low concentrations of Zr showed a red shift and a decrease in intensity of the characteristic F 2g peak at high temperatures under different atmospheres. The magnitude of the latter effect was higher under reducing atmospheres. These changes are reversible upon cooling, showing that they relate to a lattice expansion effect rather than any major chemical change to the material. In the presence of the model soot the Raman spectra of all materials was much decreased due to the absorption of the incident and scattered radiation by the soot particles. The presence of soot does not change the relative intensities or positions of the peaks in the spectra of the solid solutions. Evidence is shown for the production of a Ce 3+ -CO species following interaction between the soot and the surface at high temperature in an inert atmosphere.

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Effect of ZrO2 content on textural and structural properties of CeO2–ZrO2 solid solutions made by citrate complexation route

Cited by 158 publications

References 47 publications

Oxidation enthalpies for reduction of ceria surfaces

Oxidation enthalpies for reduction of ceria surfaces

Synergy between gold and oxygen vacancies in gold supported on Zr-doped ceria catalysts for the CO oxidation

Attempts at an in situ Raman study of ceria/zirconia catalysts in PM combustion

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