Surface chemistry of cerium oxide prepared by an isobaric thermal procedure

Fierro, J.L.G.; Mendioroz, S.; Oliván, and Montserrat

doi:10.1016/0021-9797(85)90148-1

Cited by 26 publications

(13 citation statements)

References 20 publications

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“…For surface reactions of H, first-principles studies by Chen et al 13 provided potential energy profiles at stoichiometric CeO 2 (111) and (110). Moreover, studies by Bernal et al 14 suggested that the H-CeO 2 interaction is only a surface process, while others [15][16][17][18] proposed the presence of H infiltration at CeO 2 , and therefore bulk diffusion of H is also important.…”

Section: Introductionmentioning

confidence: 99%

“…Though many studies [13][14][15][16][17][18] aiming at understanding the H-ceria interaction have been reported, comprehensive theoretical simulations involving a wide range of possible processes are still very rare. For this reason, in this paper, by using density functional theory calculations corrected by on-site Coulomb interactions (DFT + U), we extensively investigated the surface processes of H, including H diffusion, H coupling to generate H 2 and H 2 O formation accompanied by the formation of a single oxygen vacancy (O v ), as well as the bulk diffusion of H (see Fig.…”

Section: Introductionmentioning

confidence: 99%

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Role of oxygen vacancies in the surface evolution of H at CeO₂(111): a charge modification effect

Gong

2015

Phys. Chem. Chem. Phys.

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Diffusion processes and reactions of H at stoichiometric and reduced CeO2(111) surfaces have been studied by using density functional theory calculations corrected by on-site Coulomb interactions (DFT + U). Oxygen vacancies on the surface are determined to be able to significantly affect the behavior of H by modifying the charge of surface lattice O through the occurrence of Ce(3+). It has been found that, at the reduced CeO2(111) surface, the adsorption strength of H as well as the H coupling barrier can be dramatically reduced compared to those at the stoichiometric surface, while H2O formation barrier is not significantly affected. Moreover, the diffusion of H at the reduced surface or into the bulk can occur more readily than that at stoichiometric CeO2(111).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Role of oxygen vacancies in the surface evolution of H at CeO₂(111): a charge modification effect

Gong

2015

Phys. Chem. Chem. Phys.

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“…1 (compare e.g. [15,16]). It has been known that the decomposition of Ce(In) carbonates is a complex process accompanied by oxidation of cerium and formation of a number of intermediate products [15,17,18].…”

Section: Resultsmentioning

confidence: 99%

“…It has been known that the decomposition of Ce(In) carbonates is a complex process accompanied by oxidation of cerium and formation of a number of intermediate products [15,17,18]. According to Savin et al [16] the decomposition and oxidation of Ce(ut) carbonates are complete at the temperature of 460~ Perry et al [17], however, demonstrated that Ce(m) was present even in samples calcined at 500 ~ Hence it seems that preparations calcined at temperatures lower than roughly 700~ contain some intermediate products of the decomposition that have a marked negative effect upon the polishing properties.…”

Section: Resultsmentioning

confidence: 99%

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Preparation of ceria-based polishing powders from carbonates

Janoš

Petrák

1991

J Mater Sci

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The preparation of Ce0v) oxide-based polishing powders by thermal decomposition of carbonates was studied and the effect of the calcination process conditions on the properties of product was examined. High-grade polishing powders can be produced at calcination temperatures 700-1 200~ the maximum polishing efficiency is achieved by calcining at 1 000-11 00 ~ The observed dependences were interpreted from the standpoint of the present mechanochemical theory of glass polishing.

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A Theoretical Study of Surface Reduction Mechanisms of CeO₂(111) and (110) by H₂

et al. 2007

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Reaction mechanisms for the interactions between CeO(2)(111) and (110) surfaces are investigated using periodic density functional theory (DFT) calculations. Both standard DFT and DFT+U calculations to examine the effect of the localization of Ce 4f states on the redox chemistry of H(2)-CeO(2) interactions are described. For mechanistic studies, molecular and dissociative local minima are initially located by placing an H(2) molecule at various active sites of the CeO(2) surfaces. The binding energies of physisorbed species optimized using the DFT and DFT+U methods are very weak. The dissociative adsorption reactions producing hydroxylated surfaces are all exothermic; exothermicities at the DFT level range from 4.1 kcal mol(-1) for the (111) to 26.5 kcal mol(-1) for the (110) surface, while those at the DFT+U level are between 65.0 kcal mol(-1) for the (111) and 81.8 kcal mol(-1) for the (110) surface. Predicted vibrational frequencies of adsorbed OH and H(2)O species on the surfaces are in line with available experimental and theoretical results. Potential energy profiles are constructed by connecting molecularly adsorbed and dissociatively adsorbed intermediates on each CeO(2) surface with tight transition states using the nudged elastic band (NEB) method. It is found that the U correction method plays a significant role in energetics, especially for the intermediates of the exit channels and products that are partially reduced. The surface reduction reaction on CeO(2)(110) is energetically much more favorable. Accordingly, oxygen vacancies are more easily formed on the (110) surface than on the (111) surface.

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Surface chemistry of cerium oxide prepared by an isobaric thermal procedure

Cited by 26 publications

References 20 publications

Role of oxygen vacancies in the surface evolution of H at CeO₂(111): a charge modification effect

Role of oxygen vacancies in the surface evolution of H at CeO₂(111): a charge modification effect

Preparation of ceria-based polishing powders from carbonates

A Theoretical Study of Surface Reduction Mechanisms of CeO₂(111) and (110) by H₂

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Surface chemistry of cerium oxide prepared by an isobaric thermal procedure

Cited by 26 publications

References 20 publications

Role of oxygen vacancies in the surface evolution of H at CeO2(111): a charge modification effect

Role of oxygen vacancies in the surface evolution of H at CeO2(111): a charge modification effect

Preparation of ceria-based polishing powders from carbonates

A Theoretical Study of Surface Reduction Mechanisms of CeO2(111) and (110) by H2

Contact Info

Product

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Role of oxygen vacancies in the surface evolution of H at CeO₂(111): a charge modification effect

Role of oxygen vacancies in the surface evolution of H at CeO₂(111): a charge modification effect

A Theoretical Study of Surface Reduction Mechanisms of CeO₂(111) and (110) by H₂