TY - JOUR

T1 - Ab initio structure determination and quantitative disorder analysis on nanoparticles by electron diffraction tomography:

AU - Krysiak, Yaşar

AU - Barton, Bastian

AU - Marler, Bernd

AU - Neder, Reinhard B.

AU - Kolb, Ute

N1 - Funding information: This work was supported by INCOE mission project coordinated by BASF 400 SE, Germany. Yas¸ar Krysiak is very grateful to the Stipendienstiftung Rheinland-Pfalz and Forschung und Technologietransfer Universität Mainz for financial support.

PY - 2018/3

Y1 - 2018/3

N2 - Nanoscaled porous materials such as zeolites have attracted substantial attention in industry due to their catalytic activity, and their performance in sorption and separation processes. In order to understand the properties of such materials, current research focuses increasingly on the determination of structural features beyond the averaged crystal structure. Small particle sizes, various types of disorder and intergrown structures render the description of structures at atomic level by standard crystallographic methods difficult. This paper reports the characterization of a strongly disordered zeolite structure, using a combination of electron exit-wave reconstruction, automated diffraction tomography (ADT), crystal disorder modelling and electron diffraction simulations. Zeolite beta was chosen for a proof-of-principle study of the techniques, because it consists of two different intergrown polymorphs that are built from identical layer types but with different stacking sequences. Imaging of the projected inner Coulomb potential of zeolite beta crystals shows the intergrowth of the polymorphs BEA and BEB. The structures of BEA as well as BEB could be extracted from one single ADT data set using direct methods. A ratio for BEA/BEB = 48:52 was determined by comparison of the reconstructed reciprocal space based on ADT data with simulated electron diffraction data for virtual nanocrystals, built with different ratios of BEA/BEB. In this way, it is demonstrated that this smart interplay of the above-mentioned techniques allows the elaboration of the real structures of functional materials in detail - even if they possess a severely disordered structure.A routine to extract diffuse-scattering intensities caused by two-dimensional crystalline defects from tomographic electron diffraction data and an algorithm for comparison with simulated diffraction data were developed and applied to intergrown zeolite beta A and zeolite beta B.

AB - Nanoscaled porous materials such as zeolites have attracted substantial attention in industry due to their catalytic activity, and their performance in sorption and separation processes. In order to understand the properties of such materials, current research focuses increasingly on the determination of structural features beyond the averaged crystal structure. Small particle sizes, various types of disorder and intergrown structures render the description of structures at atomic level by standard crystallographic methods difficult. This paper reports the characterization of a strongly disordered zeolite structure, using a combination of electron exit-wave reconstruction, automated diffraction tomography (ADT), crystal disorder modelling and electron diffraction simulations. Zeolite beta was chosen for a proof-of-principle study of the techniques, because it consists of two different intergrown polymorphs that are built from identical layer types but with different stacking sequences. Imaging of the projected inner Coulomb potential of zeolite beta crystals shows the intergrowth of the polymorphs BEA and BEB. The structures of BEA as well as BEB could be extracted from one single ADT data set using direct methods. A ratio for BEA/BEB = 48:52 was determined by comparison of the reconstructed reciprocal space based on ADT data with simulated electron diffraction data for virtual nanocrystals, built with different ratios of BEA/BEB. In this way, it is demonstrated that this smart interplay of the above-mentioned techniques allows the elaboration of the real structures of functional materials in detail - even if they possess a severely disordered structure.A routine to extract diffuse-scattering intensities caused by two-dimensional crystalline defects from tomographic electron diffraction data and an algorithm for comparison with simulated diffraction data were developed and applied to intergrown zeolite beta A and zeolite beta B.

KW - disorder simulation

KW - electron diffraction tomography

KW - in-line electron holography

KW - polytypism

KW - zeolite beta

UR - http://www.scopus.com/inward/record.url?scp=85042882892&partnerID=8YFLogxK

U2 - 10.1107/s2053273317018277

DO - 10.1107/s2053273317018277

M3 - Article

C2 - 29493538

AN - SCOPUS:85042882892

VL - 74

SP - 93

EP - 101

JO - Acta Crystallographica Section A: Foundations and Advances

JF - Acta Crystallographica Section A: Foundations and Advances

SN - 0108-7673

IS - 2

ER -