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Mechanism of Framework Oxygen Exchange in Fe-Zeolites: A Combined DFT and Mass Spectrometry Study
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SYSNO ASEP 0389992 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Mechanism of Framework Oxygen Exchange in Fe-Zeolites: A Combined DFT and Mass Spectrometry Study Author(s) Andrikopoulos, Prokopis C. (UFCH-W) RID, ORCID
Sobalík, Zdeněk (UFCH-W) RID
Nováková, Jana (UFCH-W) RID
Sazama, Petr (UFCH-W) RID, ORCID
Sklenák, Štěpán (UFCH-W) RID, ORCID, SAISource Title ChemPhysChem. - : Wiley - ISSN 1439-4235
Roč. 14, č. 3 (2013), s. 520-531Number of pages 11 s. Language eng - English Country DE - Germany Keywords density functional theory ; iron ; zeolites Subject RIV CF - Physical ; Theoretical Chemistry R&D Projects IAA400400812 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR) GA203/09/1627 GA ČR - Czech Science Foundation (CSF) Institutional support UFCH-W - RVO:61388955 UT WOS 000315142900009 EID SCOPUS 84874055020 DOI 10.1002/cphc.201200900 Annotation The role of framework oxygen atoms in N2O decomposition [N2O(g)!N2(g) and 1=2O2(g)] over Fe-ferrierite is investigated employing a combined experimental (N2 18O decomposition in batch experiments followed by mass spectroscopy measurements) and theoretical (density functional theory calculations) approach. The occurrence of the isotope exchange indicates that framework oxygen atoms are involved in the N2O decomposition catalyzed by Fe-ferrierite. Our study, using an Fe-ferrierite sample with iron exclusively present as FeII cations accommodated in the cationic sites, shows that the mobility of framework oxygen atoms in the temperature range: 553 to 593 K is limited to the four framework oxygen atoms of the two AlO4- tetrahedra forming cationic sites that accomodate FeII. They exchange with the Fe extra-framework 18O atom originating from the decomposed N2 18O. We found, using DFT calculations, that O2 molecules facilitate the oxygen exchange. However, the corresponding calculated energy barrier of 87 kcalmol-1 is still very high and it is higher than the assumed experimental value based on the occurrence of the sluggish oxygen exchange at 553 K. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2014
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