The formation of surface stable anion vacancy states at CeO2 ultra-small crystallite dimensions
[Display omitted] ► A decrease in lattice parameter with crystallite size occurs for a terbia doped ceria sample. ► The lattice parameter variation is consistent with quantum size or surface tension effects. ► Changes in lattice parameter are not due to changes in anion vacancy concentration. ► Terb...
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| Published in: | Chemical physics letters 2012-05, Vol.536, p.109-112 |
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| Main Authors: | , , , , |
| Format: | Article |
| Language: | eng |
| Online Access: | Get full text |
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| Summary: | [Display omitted]
► A decrease in lattice parameter with crystallite size occurs for a terbia doped ceria sample. ► The lattice parameter variation is consistent with quantum size or surface tension effects. ► Changes in lattice parameter are not due to changes in anion vacancy concentration. ► Terbia and ceria form a good solid solution over the entire composition range. ► There is no evidence for increased reducibility in these mixed oxides.
The ceria–terbia solid solution system has been studied in order to assess whether ultra-small crystallites have any propensity to form stable anion vacancies at their surface. This has been suggested by many authors and has become generally accepted. The presence of anion vacancies should be manifest in lattice expansion brought about by the presence of associated Ce3+ sites. Using X-ray diffraction (XRD), no such lattice expansion was observed here and instead a lattice contraction with reduced crystallite size was observed. Further, X-ray photoelectron spectroscopy (XPS) indicates there is little evidence for the association of any vacancies with cerium cations. |
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| ISSN: | 0009-2614 1873-4448 |