MP2 Study on Decomposition of Nitrous Oxide on the Ga-ZSM-5 Научная публикация
| Журнал |
International Journal of Quantum Chemistry
ISSN: 0020-7608 , E-ISSN: 1097-461X |
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| Вых. Данные | Год: 2008, Том: 108, Номер: 14, Страницы: 2732-2743 Страниц : 12 DOI: 10.1002/qua.21817 | ||
| Ключевые слова | Ab initio, Ga-ZSM-5, MP2, MP4, Nitrous oxide decomposition, Zeolite | ||
| Авторы |
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| Организации |
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Реферат:
The reaction mechanism for nitrous oxide decomposition has been studied on gallium site in Ga-ZSM-5 using the MP2/6-31G(d) method. The active centers were taken to be mononuclear [Ga], [GaAO], and [GaO2] and the surrounding portion of the zeolite was represented by a 3T cluster, namely [AlSi2O4H8]. The first elementary step of N2O decomposition involves the formation of [GaO] and the release of N2. The metal-oxo species produced in this step then reacts with N2O again, to release N2 and form [GaO2]. The calculated activation energies at MP2 level for N2O dissociation on Ga-ZSM-5 and GaO-ZSM-5 are 15.7 and 26.5 kcal/mol at 298 K, respectively. The third elementary step of N2O decomposition on GaO2-ZSM-5 involves the formation of [GaO3] and the release of
N2. The calculated activation energy at MP2 level for N2O dissociation on GaO2-ZSM-5 is 43.7 kcal/mol.
Four-order perturbation theory (MP4//MP2) predicts that the activation barriers for nitrous oxide dissociation at 298 K on Ga-ZSM-5, GaO-ZSM-5, and GaO2-ZSM-5 are 13.9, 13.0, and 34.4 kcal/mol, respectively. The calculated energy for desorption of singlet O2 from the 3T[Ga(O)3] cluster at MP2 level is 33.4 kcal/mol. When one takes
into account the entropy gained on desorption of singlet O2, the contribution of entropy to the free energy of desorption is TS 12.3 kcal/mol at 298 K. The calculated energy of the singlet oxygen desorption from 3T[OGaO2]
cluster H (298 K) 43.57 kcal/mol and G(298 K) 30.13 kcal/mol is significantly higher than the barriers of the singlet molecular oxygen desorption from 3T[Ga(O)3] cluster.
Библиографическая ссылка:
Solkan V.N.
, Zhidomirov G.M.
MP2 Study on Decomposition of Nitrous Oxide on the Ga-ZSM-5
International Journal of Quantum Chemistry. 2008. V.108. N14. P.2732-2743. DOI: 10.1002/qua.21817 WOS Scopus РИНЦ CAPlusCA OpenAlex
MP2 Study on Decomposition of Nitrous Oxide on the Ga-ZSM-5
International Journal of Quantum Chemistry. 2008. V.108. N14. P.2732-2743. DOI: 10.1002/qua.21817 WOS Scopus РИНЦ CAPlusCA OpenAlex
Даты:
| Поступила в редакцию: | 29 апр. 2008 г. |
| Принята к публикации: | 15 мая 2008 г. |
| Опубликована online: | 14 июл. 2008 г. |
Идентификаторы БД:
| Web of science: | WOS:000260125700013 |
| Scopus: | 2-s2.0-55349095062 |
| РИНЦ: | 13581725 |
| Chemical Abstracts: | 2008:1284191 |
| Chemical Abstracts (print): | 151:409374 |
| OpenAlex: | W2123152412 |