Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Structure analysis of zeolites by rotation electron diffraction (RED)
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).ORCID iD: 0000-0001-9800-3370
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Show others and affiliations
2014 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 189, p. 115-125Article in journal (Refereed) Published
Abstract [en]

Single crystal X-ray diffraction and powder X-ray diffraction (PXRD) are powerful methods for determination of unknown crystal structures including zeolites. However, these techniques have some limitations. For instance, single crystal X-ray diffraction requires large enough crystals which are often difficult to synthesize. For powder X-ray diffraction, peak indexing and intensity extraction become difficult if there exist peak broadening caused by small crystal sizes and peak overlap due to large unit cell and high symmetry. This becomes even more complicated for samples that contain more than one phase. We developed a new rotation electron diffraction (RED) method that can overcome these limitations. Almost complete three-dimensional electron diffraction datasets can be collected from micron- or nano-sized single crystals in a transmission electron microscope by combining electron beam tilt and goniometer tilt. Here, we demonstrate the power and limitations of the RED method for ab initio structure determination of four sub-micron sized zeolites, including a calcined silicalite-1, an EUO-type germanosilicate, an FER-type aluminogermanosilicate and an AST-type aluminogermanosilicate. The latter three zeolites were found in multiphasic samples. We show how the tilt range, tilt step and resolution affect the unit cell determination, structure solution and structure refinement. The EUO-, FER- and AST-type zeolites were found in two multiphasic samples in the Al-Ge-Si system, which were also characterized by PXRD and N-2 sorption.

Place, publisher, year, edition, pages
2014. Vol. 189, p. 115-125
Keywords [en]
Electron crystallography, Electron diffraction, Unit cell determination, Zeolites, Structure determination
National Category
Chemical Sciences
Research subject
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:su:diva-103268DOI: 10.1016/j.micromeso.2013.10.014ISI: 000333853200014OAI: oai:DiVA.org:su-103268DiVA, id: diva2:719261
Conference
17th International Zeolite Conference (IZC), Moscow, Russia, July 07-12, 2013
Note

AuthorCount:9;

Available from: 2014-05-23 Created: 2014-05-12 Last updated: 2020-01-15Bibliographically approved
In thesis
1. A journey towards complete structure determination of zeolites by electron crystallography methods
Open this publication in new window or tab >>A journey towards complete structure determination of zeolites by electron crystallography methods
2020 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Electron crystallography has recently become very successful for structural studies of materials with sub-micrometer sized crystals. In this thesis two major techniques have been applied for structure elucidation – 3-dimensional electron diffraction (3D ED) and high-resolution transmission electron microscopy (HRTEM) imaging. Both can provide information about the structure at the atomic level and have been used for structure determination. During the last decade, two 3D ED methods have been used in our group; the stepwise rotation electron diffraction (RED) method developed in our lab and continuous rotation electron diffraction (cRED) where improvements on the already existing RED method were implemented. Both 3D ED methods can be used for fast structure determination of ordered crystalline materials. HRTEM imaging is very useful for structure determination of more complex and severely disordered materials. For complex structures it is often necessary to combine several methods including powder X-ray diffraction (PXRD).

   Zeolites are microporous crystalline materials. They have complex structures and often synthesized as polycrystalline powders. The aforementioned electron crystallography methods have unique advantages in elucidation of atomic structures of such zeolites. In this thesis, the development of 3D ED methods, especially from RED to cRED, is described through the journey of structure determination of four zeolites; a known pure silicate silicalite-1 for testing the RED method, and three new zeolites. The new zeolites include two extra-large pore germanosilicates ITQ-56 and SYSU-3 and one small-pore aluminosilicate EMM-37. The thesis shows the limitations and advantages of the RED and cRED methods and how different challenges in the structure determination of zeolites are tackled by the advances of 3D ED methods. Finally the thesis presents a detailed structural study of disorders in an aluminosilicate zeolite ITQ-39 by combining HRTEM, RED with sample preparation by ultramicrotomy. The structure of ITQ-39 was determined in 2012 by our group. Here three new zeolite polytypes of ITQ-39 were identified from the HRTEM images and their structure models are proposed.

   A complete structure determination of zeolites includes elucidation of the framework structure, guest species such as structure directing agent (SDA) molecules and ions in the pores, and any structural disorder in the crystal. This thesis reflects to all of these structural characteristics of zeolites, presenting the power of electron crystallography.

Place, publisher, year, edition, pages
Stockholm: Department of Materials and Environmental Chemistry, Stockholm University, 2020. p. 87
Keywords
Electron crystallography, Zeolites, Structure determination, Rotation electron diffraction, Continuous rotation electron diffraction, Disorder
National Category
Inorganic Chemistry
Research subject
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-177988 (URN)978-91-7797-964-7 (ISBN)978-91-7797-965-4 (ISBN)
Public defence
2020-02-28, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.

Available from: 2020-02-05 Created: 2020-01-15 Last updated: 2020-01-28Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full text

Search in DiVA

By author/editor
Su, JieKapaca, ElinaLiu, LeifengWan, WeiHovmöller, SvenZou, Xiaodong
By organisation
Department of Materials and Environmental Chemistry (MMK)
In the same journal
Microporous and Mesoporous Materials
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 74 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf