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On the location of iron and aluminium atoms in thermally activated AlMCM-58 and FeMCM-58 zeolites
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SYSNO ASEP 0375929 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title On the location of iron and aluminium atoms in thermally activated AlMCM-58 and FeMCM-58 zeolites Author(s) Gil, B. (PL)
Marszalek, B. (PL)
Adamski, A. (PL)
Olejniczak, Z. (PL)
Kubů, Martin (UFCH-W) RID
Čejka, Jiří (UFCH-W) RID, ORCID, SAISource Title Microporous and Mesoporous Materials. - : Elsevier - ISSN 1387-1811
Roč. 151, MAR 2012 (2012), s. 339-345Number of pages 7 s. Language eng - English Country NL - Netherlands Keywords MCM-58 ; heteroatom location ; IR, EPR and NMR spectroscopy Subject RIV CF - Physical ; Theoretical Chemistry R&D Projects GAP106/11/0819 GA ČR - Czech Science Foundation (CSF) GD203/08/H032 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z40400503 - UFCH-W (2005-2011) UT WOS 000300747000044 DOI https://doi.org/10.1016/j.micromeso.2011.10.014 Annotation FTIR study of iron and aluminium forms of zeolite MCM-58 showed that location of heteroatoms in this IFR structure depends on the type of heteroatom. The combination of the pyridine and CO adsorption allowed determination of the concentration of hydroxyls in the 12- and 5/6-rings. Both Fe and Al are generating hydroxyls pointing towards either 12-ring or 5/6-rings but the former are located in positions giving Si–OH–Fe hydroxyls pointing mainly to the 12-rings while the latter gives rise to the Si–OH–Al groups pointing primarily to the narrower 5- and 6-rings. (Al)MCM-58 undergoes only minor dehydroxylation associated with the acid sites even at temperatures as high as 700 °C, which indicates unique stabilization of Al atoms in the IFR structure. In the case of (Fe)MCM-58, dehydroxylation is more extensive. Furthermore the OH located in the 5/6-rings dehydroxylate at lower temperatures than those in the 12-rings. The study also demonstrates that the concentration of the framework and extraframework iron atoms can be determined by a simple method based on pyridine adsorption followed by IR spectroscopy. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2013
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