Surface area stability of lanthanum-doped ceria

Pijolat, Michèle; Prin, Marie-Agnès; Soustelle, Michel; Touret, Olivier; Nortier, Patrice

doi:10.1016/0167-2738(93)90196-a

Cited by 17 publications

(8 citation statements)

References 9 publications

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“…All catalysts shown have the cubic crystal structure of fluorite-type oxides. Results indicate that doping stabilizes the ceria crystal size and its resistance to sintering (grain coarsening) in agreement with previous reports (46,47). Zr-doped catalysts calcined at 650 • C have smaller crystal size (6.8 nm) than undoped CeO 2 Ce-Zr-O solid solutions with Zr content <50 at% exist in tetragonal and cubic form (48).…”

Section: Activity Testssupporting

confidence: 91%

“…Results indicate that the nature of active sites is changed after the high temperature treatment, which may be attributed to La segregation to the surface (increase of La concentration from 12.1 to 13.8% as determined by XPS analysis). La enrichment of the surface of ceria was previously reported by Pijolat et al (46). For Zr-doped CeO 2 , the observed activation energy is lower that the activation energy for the undoped and La-doped CeO 2 .…”

Section: Activity Testssupporting

confidence: 59%

See 1 more Smart Citation

Cu- and Ag-Modified Cerium Oxide Catalysts for Methane Oxidation

Kundakovic

Flytzani‐Stephanopoulos

1998

Journal of Catalysis

252

106

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Section: Activity Testssupporting

confidence: 91%

Section: Activity Testssupporting

confidence: 59%

Cu- and Ag-Modified Cerium Oxide Catalysts for Methane Oxidation

Kundakovic

Flytzani‐Stephanopoulos

1998

Journal of Catalysis

252

106

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“…The negative heat of solution which follows from these defect energies, −3.3 eV/La 2 O 3 , indicates that, in contrast to Fe, lanthanum dopants will be thermodynamically stable. Furthermore, the energy of incorporation of two triplets (table 4) suggests that there will be an upper limit to the thermodynamically favourable doping of lanthanum of 4 La, or about 5 atom%, which is consistent with experimental observations [29,30].…”

Section: (I) Neutral [2ce 3+ 4+ V O ] Tripletssupporting

confidence: 83%

Simulations of ceria nanoparticles

et al. 2015

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Atomistic computer simulations, using classical potential models, have been used to model ceria nanoparticles (NPs) with diameters of approximately 1 and 2 nm. Lattice expansion is observed in the stoichiometric 1 nm NP, consistent with experiment, indicating that reduction is not the primary driver for such expansion. Furthermore, on reduction, the 1 nm NP is found to distort significantly, offering a possible explanation for its reduced oxygen storage capacity compared to the 2 nm NP. Point defect calculations on the 2 nm NP indicate that while doping with La is energetically favourable, Fe incorporation is not.

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“…39 This effect has been explained in terms of the inhibition of the sintering ratelimiting step, the surface diffusion of cerium defects, caused by the presence of trivalent cations at the surface of CeO 2 . 40 Regarding the properties of the catalysts derived from the Fe-Ce systems investigated in this work, the most remarkable conclusion is that catalysts prepared by coprecipitation display better catalytic conversion than those prepared by physical mixing. In other words, catalysts in which an Fe-O-Ce interaction is developed in the oxide form exhibit better catalytic properties.…”

Section: Discussionmentioning

confidence: 80%

Chemical Structures of Coprecipitated Fe−Ce Mixed Oxides

Pérez‐Alonso¹,

Granados²,

Ojeda³

et al. 2005

Chem. Mater.

171

130

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Two series of Fe−Ce catalysts were prepared following two different methods: coprecipitation from Fe and Ce nitrate solutions and physical mixing of pure Fe and Ce precursors. Evidence of the presence of a chemical interaction between Fe and Ce was found in the calcined state of the coprecipitated catalysts. Such evidence was obtained with different techniques. The Fe−Ce interaction occurs through the formation of hematite-like and cubic ceria-like solid solutions. In the hematite-like solid solution, Ce cations are dissolved in the hematite structure, whereas in the cubic ceria-like solid solution Fe cations are dissolved in the ceria structure. Such interactions were absent in the samples prepared by the physical mixing. It is suggested that the Fe−Ce interaction present in the calcined state results in a strong Fe−Ce interaction in the final catalyst that defines their better catalytic properties. When tested in the Fischer−Tropsch synthesis of hydrocarbons from CO + H2 gas mixtures, the coprecipitation method series showed higher CO conversion rates, higher hydrocarbon formation rates, and a higher degree of olefinicity than the pure Fe catalyst sample and the Fe−Ce samples prepared by physical mixing.

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Surface area stability of lanthanum-doped ceria

Cited by 17 publications

References 9 publications

Cu- and Ag-Modified Cerium Oxide Catalysts for Methane Oxidation

Cu- and Ag-Modified Cerium Oxide Catalysts for Methane Oxidation

Simulations of ceria nanoparticles

Chemical Structures of Coprecipitated Fe−Ce Mixed Oxides

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