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Structural study of zeolites utilizing novel electron crystallographic methods: A voyage into the world of zeolite structures
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Electron crystallography has evolved as a powerful method for structural characterization of a wide range of materials. It has two significant advantages over other methods for structure determination, e.g. X-ray diffraction. Electrons interact much more strongly with matter compared to X-rays and they can be focused by electromagnetic lenses to form images with atomic resolution. These advantages make electron crystallography a unique tool for characterization of crystalline materials suffering from small crystal size and complex or disordered structures.

     Zeolites are a class of microporous materials with significance in several applications. They often possess complex and disordered structures, which demand large efforts in the structure determination.

     Over the last years, two new electron crystallographic methods have been developed; the rotation electron diffraction (RED) and the structure projection reconstruction from a through-focus series of high resolution transmission electron microscopy (HRTEM) images. In this thesis, they will be applied for structure determination of four new zeolite structures, including EMM-25 and EMM-23 with two ordered structures, and ITQ-39 and ITQ-38 with disordered structures. Each of the structure solutions have different challenges to overcome. The high silica borosilicate EMM-25 was solved by the RED method. The aluminosilicate EMM-23 was solved by a combination of HRTEM and RED. The structure solution of two materials with disordered structures, ITQ-39 and ITQ-38, will be described. For materials containing disorders, structure projection images are of utmost importance.

     Furthermore, the mesoporosity inside hierarchically porous ZSM-5 crystals was studied by a combination of focused ion beam (FIB) and HRTEM imaging. The last part of this thesis explores STEM imaging for use in structure determination from 3D reconstruction.

Place, publisher, year, edition, pages
Stockholm: Department of Materials and Environmental Chemistry (MMK), Stockholm University , 2013. , 104 p.
Keyword [en]
Electron crystallography, zeolites, structure determination, disorder, electron microscopy
National Category
Inorganic Chemistry
Research subject
Structural Chemistry
Identifiers
URN: urn:nbn:se:su:diva-95870ISBN: 978-91-7447-810-5 (print)OAI: oai:DiVA.org:su-95870DiVA: diva2:661984
Public defence
2013-12-16, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 12, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defence the following papers were unpublished and had a status as follows: Papers 4 and 5: Manuscipts; Paper 10: Manuscript

Available from: 2013-11-24 Created: 2013-11-05 Last updated: 2013-11-26Bibliographically approved
List of papers
1. Stacking disorders in zeolites and open-frameworks - structure elucidation and analysis by electron crystallography and X-ray diffraction
Open this publication in new window or tab >>Stacking disorders in zeolites and open-frameworks - structure elucidation and analysis by electron crystallography and X-ray diffraction
2013 (English)In: Zeitschrift fur Kristallographie, ISSN 0044-2968, Vol. 228, no 1, 11-27 p.Article, review/survey (Refereed) Published
Abstract [en]

Intergrowth and stacking disorders are often found in minerals and synthetic zeolites and inorganic open-frameworks. Structure elucidation of stacking disorders in these materials have been difficult and structure solution of stacking disorders in unknown zeolites and open-frameworks has been challenging. There exist no standard methods for structure analysis of such disordered materials. In this review we present various stacking disorders and intergrowth in a number of representative zeolite families containing stacking disorders. These include zeolite beta, SSZ-26/SSZ-33, ITQ-39, ABC-6, ZSM-48, SSZ-31, UTD-1, faujasite FAU/EMT, pentasil ZSM-5/ZSM-11, ITQ-13/ITQ-34, ITQ-22/ITQ-38 etc. Stacking disorders in open-frameworks containing mixed coordinations, including titanosilicates ETS-10 and ETS-4, and the silicogermanate SU-JU-14 are also described. Various crystallographic methods used for solving disordered structures are summarized. The methods include powder X-ray diffraction (PXRD), electron diffraction, high resolution transmission electron microscopy (HRTEM), and single-crystal X-ray diffraction. Examples of model building combined with simulations of PXRD and single crystal X-ray diffraction to verify the structure models are given.

Keyword
Zeolites, Open-frameworks, Stacking disorders, Electron crystallography, Structure analysis
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-88953 (URN)10.1524/zkri.2012.1564 (DOI)000315475900003 ()
Funder
Vinnova
Note

AuthorCount:2;

Available from: 2013-04-17 Created: 2013-04-08 Last updated: 2017-12-06Bibliographically approved
2. Structural Determination of Ordered Porous Solids by Electron Crystallography
Open this publication in new window or tab >>Structural Determination of Ordered Porous Solids by Electron Crystallography
2014 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 24, no 2 (SI), 182-199 p.Article, review/survey (Refereed) Published
Abstract [en]

Knowing the structure of porous materials is essential for understanding their properties and exploiting them for applications. Electron crystallography has two main advantages compared to X-ray diffraction for structure determination. Crystals too small or too complicated to be studied by X-ray diffraction can be studied by electron crystallography. The crystallographic structure factor phase information, which is lost in X-ray diffraction, can be obtained from high-resolution transmission electron microscopy (HRTEM) images. Here, different electron microscopic techniques and their applications for structure determination of porous materials are reviewed. The recently developed automated diffraction tomography (ADT), the rotation electron diffraction (RED), and the through-focus structure projection reconstruction (QFcous) methods make the structure determination by electron crystallography more feasible for non-TEM experts and as efficient as that by X-ray diffraction. How the various electron crystallographic methods are chosen are demonstrated and these methods used for solving different structural problems in porous materials. The benefits of combining electron crystallography and X-ray diffraction for studying complex zeolite structures are also shown. A large number of examples are given to demonstrate the use of various electron crystallographic techniques for structure determination of zeolites, metal-organic frameworks and ordered mesoporous materials. These electron crystallographic methods are general and can also be used for structural studies of other functional materials.

National Category
Nano Technology Materials Engineering Materials Chemistry
Identifiers
urn:nbn:se:su:diva-95866 (URN)10.1002/adfm.201301949 (DOI)000330963000002 ()
Funder
Knut and Alice Wallenberg FoundationVinnovaSwedish Research Council
Note

AuthorCount: 3;

Available from: 2013-11-05 Created: 2013-11-05 Last updated: 2017-12-06Bibliographically approved
3. Synthesis and characterization of pure silica zeolite beta obtained by an aging-drying method
Open this publication in new window or tab >>Synthesis and characterization of pure silica zeolite beta obtained by an aging-drying method
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2011 (English)In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 143, no 1, 196-205 p.Article in journal (Refereed) Published
Abstract [en]

Pure silica zeolite beta materials were synthesized by an unconventional method of aging and drying the starting gels at room temperature followed by the conventional hydrothermal treatment. In addition, organic solvents were added to selected samples as complementary structure directing agents (SDA). The influence of the aging-drying method, complementary SDA addition and crystallization time upon the synthesis of pure silica zeolite beta were studied. Samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), thermogravimetric analyses (TGA) and nitrogen adsorption. Results revealed that the aging-drying process increased crystallization rate, produced crystals with unique morphology and scaled-surface and allowed polymorph A enrichments to about 68-70%. It was also found that addition of organic solvents during the thermal treatment tunes the crystal morphology but, does not affect the polymorphic enrichment.

Keyword
Al-Si-beta, Ti-Si-beta, Aging-drying method, Polymorphic enrichment, Fluoride medium
National Category
Chemical Sciences Physical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:su:diva-68900 (URN)10.1016/j.micromeso.2011.02.030 (DOI)000291524700026 ()
Note
5Available from: 2012-01-09 Created: 2012-01-09 Last updated: 2017-12-08Bibliographically approved
4. Rational synthesis and structure of a borosilicate zeolite with intersecting 10- and 11-ring channels
Open this publication in new window or tab >>Rational synthesis and structure of a borosilicate zeolite with intersecting 10- and 11-ring channels
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-95867 (URN)
Available from: 2013-11-05 Created: 2013-11-05 Last updated: 2014-11-10
5. The first stable high silica zeolite with extra-large 24-ring channels
Open this publication in new window or tab >>The first stable high silica zeolite with extra-large 24-ring channels
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(English)Manuscript (preprint) (Other academic)
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-95869 (URN)
Available from: 2013-11-05 Created: 2013-11-05 Last updated: 2013-11-05
6. A New Aluminosilicate Molecular Sieve with a System of Pores between Those of ZSM-5 and Beta Zeolite
Open this publication in new window or tab >>A New Aluminosilicate Molecular Sieve with a System of Pores between Those of ZSM-5 and Beta Zeolite
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2011 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 133, no 24, 9497-9505 p.Article in journal (Refereed) Published
Abstract [en]

A new aluminosilicate zeolite (ITQ-39) has been synthesized. This is an extensively faulted structure with very small domains that makes the structure elucidation very difficult. However, a combination of adsorption spectroscopy and reactivity studies with selected probe molecules suggests that the pore structure of ITQ-39 is related to that of Beta zeolite, with a three-directional channel system with large pores (12-MR), but with an effective pore diameter between those of Beta and ZSM-5, or a three-directional channel system with interconnected large (12-MR) and medium pores (10-MR). The pore topology of ITQ-39 is very attractive for catalysis and shows excellent results for the preparation of cumene by alkylation of benzene, while it can be a promising additive for FCC.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-67579 (URN)10.1021/ja2015394 (DOI)000291915100063 ()
Note
authorCount :8Available from: 2011-12-29 Created: 2011-12-29 Last updated: 2017-12-08Bibliographically approved
7. Structure and catalytic properties of the most complex intergrown zeolite ITQ-39 determined by electron crystallography
Open this publication in new window or tab >>Structure and catalytic properties of the most complex intergrown zeolite ITQ-39 determined by electron crystallography
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2012 (English)In: Nature Chemistry, ISSN 1755-4330, E-ISSN 1755-4349, Vol. 4, 188-194 p.Article in journal (Refereed) Published
Abstract [en]

Porous materials such as zeolites contain well-defined pores in molecular dimensions and have important industrial applications in catalysis, sorption and separation. Aluminosilicates with intersecting 10- and 12-ring channels are particularly interesting as selective catalysts. Many porous materials, especially zeolites, form only nanosized powders and some are intergrowths of different structures, making structure determination very challenging. Here, we report the atomic structures of an aluminosilicate zeolite family, ITQ-39, solved from nanocrystals only a few unit cells in size by electron crystallography. ITQ-39 is an intergrowth of three different polymorphs, built from the same layer but with different stacking sequences. ITQ-39 contains stacking faults and twinning with nano-sized domains, being the most complex zeolite ever solved. The unique structure of ITQ-39, with a three-dimensional intersecting pairwise 12-ring and 10-ring pore system, makes it a promising catalyst for converting naphtha into diesel fuel, a process of emerging interest for the petrochemical industry.

Keyword
Catalysis, Materials chemistry
National Category
Natural Sciences Inorganic Chemistry
Research subject
Structural Chemistry
Identifiers
urn:nbn:se:su:diva-74963 (URN)10.1038/nchem.1253 (DOI)000300628900014 ()
Available from: 2012-04-01 Created: 2012-04-01 Last updated: 2017-12-07Bibliographically approved
8. Synthesis Design and Structure of a Multipore Zeolite with Interconnected 12-and 10-MR Channels
Open this publication in new window or tab >>Synthesis Design and Structure of a Multipore Zeolite with Interconnected 12-and 10-MR Channels
Show others...
2012 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 14, 6473-6478 p.Article in journal (Refereed) Published
Abstract [en]

A new molecular sieve, ITQ-38, containing interconnected large and medium pores in its structure has been synthesized. The rational combination of dicationic piperidine-derivative molecules as organic structure directing agents (OSDAs) with germanium and boron atoms in alkaline media has allowed the synthesis of ITQ-38 zeolite. High-resolution transmission electron microscopy (HRTEM) has been used to elucidate the framework topology of ITQ-38, revealing the presence of domains of perfect ITQ-38 crystals as well as very small areas containing nanosized ITQ-38/ITQ-22 intergrowths. The structure of ITQ-38 is highly related to ITQ-22 and the recently described polymorph C of ITQ-39 zeolite. It shares a common building layer with ITQ-22 and contains the same building unit as the polymorph C of ITQ-39. All three structures present similar framework density, 16.1 T atoms/1000 angstrom(3).

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-76075 (URN)10.1021/ja301082n (DOI)000302524800057 ()
Note
8Available from: 2012-05-08 Created: 2012-05-08 Last updated: 2017-12-07Bibliographically approved
9. ZSM-5 Zeolite Single Crystals with b-Axis-Aligned Mesoporous Channels as an Efficient Catalyst for Conversion of Bulky Organic Molecules
Open this publication in new window or tab >>ZSM-5 Zeolite Single Crystals with b-Axis-Aligned Mesoporous Channels as an Efficient Catalyst for Conversion of Bulky Organic Molecules
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2012 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 10, 4557-4560 p.Article in journal (Refereed) Published
Abstract [en]

The relatively small and sole micropores in zeolite catalysts strongly influence the mass transfer and catalytic conversion of bulky molecules. We report here aluminosilicate zeolite ZSM-5 single crystals with b-axis-aligned mesopores, synthesized using a designed cationic amphiphilic copolymer as a mesoscale template. This sample exhibits excellent hydrothermal stability. The orientation of the mesopores was confirmed by scanning and transmission electron microscopy. More importantly, the b-axis-aligned mesoporous ZSM-5 shows much higher catalytic activities for bulky substrate conversion than conventional ZSM-5 and ZSM-5 with randomly oriented mesopores. The combination of good hydrothermal stability with high activities is important for design of novel zeolite catalysts. The b-axis-aligned mesoporous ZSM-5 reported here shows great potential for industrial applications.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-76147 (URN)10.1021/ja300078q (DOI)000301990600027 ()
Note
9Available from: 2012-05-09 Created: 2012-05-09 Last updated: 2017-12-07Bibliographically approved
10. 3D reconstruction of atomic structures from high angle annular dark field (HAADF) STEM images
Open this publication in new window or tab >>3D reconstruction of atomic structures from high angle annular dark field (HAADF) STEM images
(English)Manuscript (preprint) (Other academic)
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:su:diva-95868 (URN)
Available from: 2013-11-05 Created: 2013-11-05 Last updated: 2013-11-05

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