Effect of HF concentration on the composition and distribution of Ge species in the framework of ITQ-13 and ITQ-17 zeolites

Handle URI:
http://hdl.handle.net/10754/562696
Title:
Effect of HF concentration on the composition and distribution of Ge species in the framework of ITQ-13 and ITQ-17 zeolites
Authors:
Liu, Xiaolong; Ravon, Ugo; Tuel, Alain
Abstract:
Two germanosilicates with zeolitic structures, namely ITQ-13 and ITQ-17, have been synthesized from gels containing various amounts of hydrofluoric acid. Although both zeolites possess similar compositions, they differ not only by their pore size and framework topology but also by the nature of the cavities surrounding fluoride species in the structure. For ITQ-17, in which fluoride is almost exclusively located in D4R units, a decrease in HF concentration in the gel has no influence on the fluoride content in the zeolite. However, it favors the incorporation of germanium species in the framework, particularly in D4R units. Zeolites obtained at low HF concentrations are characterized by high Ge contents and Si/Ge atomic ratios close to 1 in D4R units. In the case of ITQ-13, the possibility for fluoride to reside not only in D4R units but also in the larger [415262] cages minimizes the influence of the HF concentration on the zeolite framework composition. Reducing the HF concentration in the gel has no effect on the Si/Ge ratio in the final zeolite but it decreases the fluoride content in the structure. At low HF concentration, fluoride is absent from [415262] cages and is almost exclusively present in all-silica D4R units. As the concentration increases, fluoride starts to occupy Ge-rich D4R and [415 262] cages, as clearly evidenced by 19F NMR. By contrast to ITQ-17, the amount of HF in the gel does not influence the distribution of Ge species in the framework. © 2012 Published by Elsevier Inc.
KAUST Department:
KAUST Catalysis Center (KCC)
Publisher:
Elsevier
Journal:
Microporous and Mesoporous Materials
Issue Date:
Apr-2013
DOI:
10.1016/j.micromeso.2012.11.038
Type:
Article
ISSN:
13871811
Sponsors:
This publication is based on the work supported by Award No. UK-C0017, made by King Abdullah University of Science and Technology (KAUST).
Appears in Collections:
Articles; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorLiu, Xiaolongen
dc.contributor.authorRavon, Ugoen
dc.contributor.authorTuel, Alainen
dc.date.accessioned2015-08-03T11:01:54Zen
dc.date.available2015-08-03T11:01:54Zen
dc.date.issued2013-04en
dc.identifier.issn13871811en
dc.identifier.doi10.1016/j.micromeso.2012.11.038en
dc.identifier.urihttp://hdl.handle.net/10754/562696en
dc.description.abstractTwo germanosilicates with zeolitic structures, namely ITQ-13 and ITQ-17, have been synthesized from gels containing various amounts of hydrofluoric acid. Although both zeolites possess similar compositions, they differ not only by their pore size and framework topology but also by the nature of the cavities surrounding fluoride species in the structure. For ITQ-17, in which fluoride is almost exclusively located in D4R units, a decrease in HF concentration in the gel has no influence on the fluoride content in the zeolite. However, it favors the incorporation of germanium species in the framework, particularly in D4R units. Zeolites obtained at low HF concentrations are characterized by high Ge contents and Si/Ge atomic ratios close to 1 in D4R units. In the case of ITQ-13, the possibility for fluoride to reside not only in D4R units but also in the larger [415262] cages minimizes the influence of the HF concentration on the zeolite framework composition. Reducing the HF concentration in the gel has no effect on the Si/Ge ratio in the final zeolite but it decreases the fluoride content in the structure. At low HF concentration, fluoride is absent from [415262] cages and is almost exclusively present in all-silica D4R units. As the concentration increases, fluoride starts to occupy Ge-rich D4R and [415 262] cages, as clearly evidenced by 19F NMR. By contrast to ITQ-17, the amount of HF in the gel does not influence the distribution of Ge species in the framework. © 2012 Published by Elsevier Inc.en
dc.description.sponsorshipThis publication is based on the work supported by Award No. UK-C0017, made by King Abdullah University of Science and Technology (KAUST).en
dc.publisherElsevieren
dc.subjectFluorideen
dc.subjectGermaniumen
dc.subjectITQ-13en
dc.subjectITQ-17en
dc.subjectZeoliteen
dc.titleEffect of HF concentration on the composition and distribution of Ge species in the framework of ITQ-13 and ITQ-17 zeolitesen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalMicroporous and Mesoporous Materialsen
dc.contributor.institutionUniv Lyon 1, Inst Rech Catalyse & Environm Lyon IRCELYON, CNRS, UMR 5256, F-69626 Villeurbanne, Franceen
kaust.authorRavon, Ugoen
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