Invited Review: Some recent developments in the atomic-scale characterization of structural and transport properties of ceria-based catalysts and ionic conductors

Yashima, Masatomo

doi:10.1016/j.cattod.2015.03.034

Cited by 76 publications

(55 citation statements)

References 94 publications

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“…[ 138 ] However, it is important to notice that despite many years of investigations, there are still disagreements on the phase diagram of Ce x Zr 1-x O 2 solid solutions and their phase boundaries, besides problems related to structural aspects and chemical properties. [ 138 ] However, it is important to notice that despite many years of investigations, there are still disagreements on the phase diagram of Ce x Zr 1-x O 2 solid solutions and their phase boundaries, besides problems related to structural aspects and chemical properties.…”

Section: Controlled Synthesis Of Ceria-zirconia Solid Solutionsmentioning

confidence: 99%

Recent Progress in Well‐Controlled Synthesis of Ceria‐Based Nanocatalysts towards Enhanced Catalytic Performance

Sun

Yan

2016

Advanced Energy Materials

147

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The unique electronic configuration and structural properties of ceria make ceria‐based nanomaterials such as morphology‐dependent ceria nanocrystals, rare earth‐doped ceria‐zirconia solid solutions and noble metal‐ceria nanocomposites effective promoters in three‐way catalysts for low‐temperature water‐gas‐shift reaction, preferential oxidation of traces of CO, the treatment of toxic auto‐mobile exhaust, etc. The activities of nanoceria catalysts can be determined by their morphologies, oxygen vacancies, interfacial structures and the type of exposed crystal surfaces, as well as the synergistic effect exhibited by nanocomposites. In this review, the state‐of‐the‐art developments in the well‐controlled synthesis of ceria‐based nanocatalysts and their applications in both environmental and energy fields is summarized. The involved reaction mechanisms are also briefly introduced, and eventually an outlook in the design of novel nanoceria catalysts for valuable energy applications is addressed.

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Section: Controlled Synthesis Of Ceria-zirconia Solid Solutionsmentioning

confidence: 99%

Recent Progress in Well‐Controlled Synthesis of Ceria‐Based Nanocatalysts towards Enhanced Catalytic Performance

Sun

Yan

2016

Advanced Energy Materials

147

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“…Cerium oxide (CeO 2 ) is a technologically important material, with applications ranging from catalysis in automotive exhaust [1][2][3][4][5], solid-oxide fuel cells [6,7], and water-gas shift reactions [8,9]. The outstanding functionality of CeO 2 in these applications is largely due to its great oxygen storage/release capability (OSC).…”

Section: Introductionmentioning

confidence: 99%

Disentangling the role of small polarons and oxygen vacancies in CeO2

et al. 2017

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The outstanding performance of cerium oxide (CeO 2 ) as ion conductor or catalyst strongly depends on the ease of Ce 4+ ↔Ce 3+ conversion and oxygen vacancyformation. An accurate description of Ce 3+ and oxygen vacancy is therefore essential to further progress in this area. Using the HSE06 hybrid functional, we investigate the formation and migration of small polarons (Ce 3+ ) and their interaction with oxygen vacancies in CeO 2 , considering the small polaron and vacancy as independent entities.Oxygen vacancies are double donors and can bind up to two small polarons, forming a positively charged or neutral complex. We compute the electron self-trapping energy (i.e., energy gain when forming a small polaron), the small-polaron migration barrier, vacancy formation and migration energies, and vacancy-polaron binding energies. We find that small polarons weakly bind to oxygen vacancies, yet this interaction significantly contributes to the activation energy for hopping electronic conductivity.The results are compared with previous calculations and discussed in the light of available experimental data.

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“…3),5)7), 9) The crystal structure of the Fd 3m pyrochlore-type oxides A 2 B 2 O 7 can be regarded as a "vacancy-ordered fluorite-type structure" where A is a larger cation as Yb 3+ and Gd . Since some of the Fd 3m pyrochlore-type oxides exhibit high oxide-ion conductivity, 10)13) their crystal structures and oxide-ion conduction mechanism have extensively been studied by X-ray and neutron diffraction experiments, 1 is one of the highest oxide-ion conductors with the pyrochlore-type structure.…”

Section: Introductionmentioning

confidence: 99%

Experimental visualization of oxide-ion diffusion paths in pyrochlore-type Yb2Ti2O7

Uno

Fujii

Niwa

et al. 2018

J. Ceram. Soc. Japan

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Crystal structure and neutron scattering length density distribution of a pyrochlore-type ytterbium titanate Yb 2 Ti 2 O 7 have been investigated by in situ neutron powder diffraction measurements at 293 and 1173 K, Rietveld analysis and maximum-entropy method (MEM). In the MEM neutron scattering length density distributions of Yb 2 Ti 2 O 7 , the oxide ion O 48f bonding to Ti cation was relatively localized at lower temperature of 293 K, while it was largely distributed at a higher temperature of 1173 K. At 1173 K, one oxide-ion diffusion path along the ©110ª unshared edge of TiO 6 octahedron was clearly visualized and the other oxide-ion diffusion path along ©100ª, strictly ©2 ¹8x(O 48f ) + 3 8x(O 48f ) ¹ 3ª, shared edge of TiO 6 octahedron was also indicated. Here x(O 48f ) is the atomic coordinate x of O 48f anion. The MEM neutron scattering length density distribution and difference bond valence sum map at 1173 K strongly suggested that the energy barrier for oxide-ion migration along ©110ª directions was lower than that along the ©100ª one. Oxide ions three-dimensionally diffuse through both the ©110ª and ©100ª paths across the unit cell.

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Invited Review: Some recent developments in the atomic-scale characterization of structural and transport properties of ceria-based catalysts and ionic conductors

Cited by 76 publications

References 94 publications

Recent Progress in Well‐Controlled Synthesis of Ceria‐Based Nanocatalysts towards Enhanced Catalytic Performance

Recent Progress in Well‐Controlled Synthesis of Ceria‐Based Nanocatalysts towards Enhanced Catalytic Performance

Disentangling the role of small polarons and oxygen vacancies in CeO2

Experimental visualization of oxide-ion diffusion paths in pyrochlore-type Yb<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>

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