Kinetics of Oxygen Exchange over CeO2-ZrO2 Fluorite-Based Catalysts Научная публикация
| Журнал |
The Journal of Physical Chemistry A
ISSN: 1089-5639 , E-ISSN: 1520-5215 |
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| Вых. Данные | Год: 2007, Том: 111, Номер: 20, Страницы: 4498-4505 Страниц : 8 DOI: 10.1021/jp0687706 | ||||
| Ключевые слова | Adsorption; Catalysts; Desorption; Oxygen; Reaction kinetics; Zirconia | ||||
| Авторы |
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| Организации |
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Информация о финансировании (1)
| 1 | Российский фонд фундаментальных исследований | 05-03-34761 |
Реферат:
The kinetics of 18O/16O isotopic exchange over CeO2−ZrO2−La2O3 and Pt/CeO2−ZrO2 catalysts have been investigated under the conditions of dynamic adsorption−desorption equilibrium at atmospheric pressure and a temperature range of 650−850 °C. The rates of oxygen adsorption−desorption on Pt sites, support surface, oxygen transfer (spillover) from Pt to the support as well as the amount of oxygen accumulated in the oxide bulk, and oxygen diffusion coefficient were estimated. The nanocrystalline structure of lanthana-doped ceria-zirconia prepared via the Pechini route with a developed network of domain boundaries and specific defects guarantees a high oxygen mobility in the oxide bulk (D = (1.5 ÷ 2.0)·10-18 m2 s-1 at 650 °C) and allows accumulation of over-stoichiometric/excess oxygen. For Pt/CeO2−ZrO2, oxygen transfer from Pt to support (characteristic time < 10-2 s) was shown to be responsible for the fast exchange between the gas-phase oxygen and oxygen adsorbed on the mixed oxide surface. The rate of direct exchange between the phase and surface oxygen is increased as well due to the increased concentration (up to 2 monolayers) of surface/near subsurface oxygen species accumulated on the oxygen vacancies (originated from the incorporation of highly dispersed Pt atoms). The characteristic time of diffusion of the oxygen localized in the subsurface layers is about 1 s. The overall quantity of over-stoichiometric oxygen and/or hydroxyl groups accumulated in the bulk can reach the equivalent of 10 monolayers, and characteristic time of oxygen diffusion within the bulk is about 20 s. All these kinetic data are required for the further step of modeling partial oxidation of hydrocarbons under steady- and unsteady-state conditions.
Библиографическая ссылка:
Sadovskaya E.M.
, Ivanova Y.A.
, Pinaeva L.G.
, Grasso G.
, Kuznetsova T.G.
, van Veen A.
, Sadykov V.A.
, Mirodatos C.
Kinetics of Oxygen Exchange over CeO2-ZrO2 Fluorite-Based Catalysts
The Journal of Physical Chemistry A. 2007. V.111. N20. P.4498-4505. DOI: 10.1021/jp0687706 WOS Scopus РИНЦ CAPlusCA PMID OpenAlex
Kinetics of Oxygen Exchange over CeO2-ZrO2 Fluorite-Based Catalysts
The Journal of Physical Chemistry A. 2007. V.111. N20. P.4498-4505. DOI: 10.1021/jp0687706 WOS Scopus РИНЦ CAPlusCA PMID OpenAlex
Даты:
| Поступила в редакцию: | 20 дек. 2006 г. |
| Принята к публикации: | 5 мар. 2007 г. |
| Опубликована в печати: | 1 мая 2007 г. |
| Опубликована online: | 2 мая 2007 г. |
Идентификаторы БД:
| Web of science: | WOS:000246569300048 |
| Scopus: | 2-s2.0-34250180228 |
| РИНЦ: | 13537894 |
| Chemical Abstracts: | 2007:477612 |
| Chemical Abstracts (print): | 147:80472 |
| PMID (PubMed): | 17472353 |
| OpenAlex: | W2013823625 |