Cationic Surface Reconstructions on Cerium Oxide Nanocrystals: An Aberration-Corrected HRTEM Study

Bhatta, Umananda M.; Ross, I. M.; Sayle, Thi X. T.; Sayle, Dean C.; Parker, Stephen C.; Reid, David L.; Seal, Sudipta; Kumar, Amit; Möbus, Günter

doi:10.1021/nn2037576

Cited by 56 publications

(55 citation statements)

References 33 publications

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“…It is important to clarify whether cuboid ceria surfaces with {100}-type faces larger than {111} behave in the same way. Fig 3(a, b) confirms extensive atomic hopping on {100} on a hydrothermal specimen with mainly cubes, while for the first time (minor) hopping on the adjacent {111} face, probably due to overspill of atoms from the very active corner region, is observed (see [13] for further details). Simulation parameters used were similar except for the defocus value which was +25 nm and the thickness of the ROI was found to be 8.0 nm.…”

Section: Resultsmentioning

confidence: 71%

Atomic motion on various surfaces of ceria nanoparticles in comparison

Bhatta

Ross

Saghi

et al. 2012

J. Phys.: Conf. Ser.

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Section: Resultsmentioning

confidence: 71%

Atomic motion on various surfaces of ceria nanoparticles in comparison

Bhatta

Ross

Saghi

et al. 2012

J. Phys.: Conf. Ser.

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“…32,47 As was revealed by Wu et al, 51 the turnover frequency of CO oxidation on the planes of the CeO 2 nanocrystals drops in the sequence (110) > (100) > (111), which is in agreement with the theoretical prediction and the experimental results. [52][53][54][55] Specifically, the ease of oxygen extraction from the surface plane of ceria is directly related to its catalytic reactivity, which in turn reveals the crucial role of oxygen vacancies on ceria surfaces in the adsorption and activation of O 2 , thus related to CO oxidation. By using Raman and TPD measurements, the role of oxygen vacancies in adsorption of O 2 was carefully analysed.…”

Section: View Article Onlinementioning

confidence: 99%

Shape dependence of nanoceria on complete catalytic oxidation of o-xylene

Wang

Zhang

et al. 2016

Catal. Sci. Technol.

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BTX (benzene, toluene, and xylene) in atmosphere, mainly emitted from various industrial processes and transportation activities, are of particular concern due to their potentially highly toxic effects on human health. Catalytic oxidation of o-xylene was investigated on nanosized CeO 2 particles, cubes, and rods, among which rods show the highest activity, which is comparable with those of traditional noble-metal catalysts. CeO 2 nanorods also exhibit long durability for o-xylene oxidation, without deactivation during a 50 h time-on stream test. Over the CeO 2 rods and particles, the presence of water vapor slightly decreased o-xylene conversion, while water vapor enhanced o-xylene oxidation on the CeO 2 cubes.High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, positron annihilation spectroscopy, and O 2 temperature-programmed desorption measurements revealed that ceria rods enclosed by (111) and (100) facets exhibit the highest concentration of oxygen vacancy clusters (VCs), the presence of which promoted the adsorption of molecular oxygen. The lower the temperature for desorption of chemisorbed O 2 species is, the higher is the activity for o-xylene oxidation, identifying the key role of VCs in this reaction via the activation of molecular oxygen over nanoceria.The finding may also be fundamental for designing ceria-based catalysts with better performance for catalytic oxidation of volatile organic compounds.

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“…2a is not high enough for this purpose. As noted before [20,[29][30][31][32], however, the mobility of atoms at ceria (100) surface is quite high and the three types terminations discussed above could coexist at the surface. In fact, the mobility of oxygen inside CeO 2 is also high, making it a good oxygen reservoir in catalytic applications or ionic conductor in solid oxide fuel cells [33].…”

Section: +mentioning

confidence: 68%

Atomic layer reversal on CeO2 (100) surface

Huang

Zhu

et al. 2017

Sci. China Mater.

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The structure and properties of CeO 2 surfaces have been intensively studied due to their importance in a lot of surface-related applications. Since most of surface techniques probe the structure information inside the outermost surface plane, the subsurface structure information has been elusive in many studies. Using the profile imaging with aberration-corrected transmission electron microscopy, the structure information in both the outermost layer and the sublayers of the CeO 2 (100) surface has been obtained. In addition to the normal structures that have been reported before, where the surface is Ce-or O-terminated, a metastable surface has been discovered. In the new structure, there is an atomic layer reversal between the outermost layer and the sublayer, giving a structure with O as the outermost layer for the stoichiometry of normal Ce-terminated surface. The charge redistribution for the polarity compensation has also been changed relative to the normal surface.Keywords: surface structure, ceria, atomic layer reversal, aberration-corrected TEM, first-principles calculations Materials based on CeO 2 , owing to their outstanding physical and chemical properties, have played important roles in solar cells [1], solid-oxide fuel cells [2,3], UV blockers [4-6] and a variety of catalytic reactions like three-way automotive catalytic converters, the production and purification of hydrogen [7][8][9][10]. Many of these applications are closely related to the specific local structures on CeO 2 surface such as islands, steps, oxygen vacancies and Ce 3+ ions. For instance, the high capacity of CeO 2 in oxygen storage-release is largely contributed by the oxygen vacancies that can be quickly formed and eliminated [11]; the abundant oxygen vacancies in Ru/CeO 2 catalysts serve as the active site for CO 2 activation [12] and also behave as the active sites for many catalytic reactions with the accompanied reduction of Ce 4+ ions [13]; the high activity of Au/ceria catalysts in the water-gas shift reaction has been traced back to the ionic Au species that only strongly associated with cerium-oxygen surface [14,15]. Hence, CeO 2 surfaces have been attracting large amount of investigation. In previous studies on the surface of CeO 2 , single crystals were usually chosen as the main research objects. Scanning tunneling microscope (STM) and atomic force microscope (AFM) were commonly used in structural characterization [16][17][18]. Most of research findings are focused on the (111) surface of ceria single crystals or epitaxial thin films. Namai et al. [16,17] observed the structure and dynamic behavior of CeO 2 (111) surfaces in STM, and visualized the surface oxygen atoms, oxygen point defects, and multiple oxygen defects on oxygenterminated CeO 2 (111) surface through noncontact AFM. Esch et al. [18] unraveled the local structure of oxygen vacancies on the (111) surface and subsurface combining high resolution STM with density functional calculations. They found that the electrons left behind by released oxyge...

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Cationic Surface Reconstructions on Cerium Oxide Nanocrystals: An Aberration-Corrected HRTEM Study

Cited by 56 publications

References 33 publications

Atomic motion on various surfaces of ceria nanoparticles in comparison

Atomic motion on various surfaces of ceria nanoparticles in comparison

Shape dependence of nanoceria on complete catalytic oxidation of o-xylene

Atomic layer reversal on CeO2 (100) surface

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