title: Morphology-dependent zeolite intergrowth structures leading to distinct internal and outer-surface molecular diffusion barriers.
abstract: Zeolites play a crucial part in acid-base heterogeneous catalysis. Fundamental insight into their internal architecture is of great importance for understanding their structure-function relationships. Here, we report on a new approach correlating confocal fluorescence microscopy with focused ion beam-electron backscatter diffraction, transmission electron microscopy lamelling and diffraction, atomic force microscopy and X-ray photoelectron spectroscopy to study a wide range of coffin-shaped MFI-type zeolite crystals differing in their morphology and chemical composition. This powerful combination demonstrates a unified view on the morphology-dependent MFI-type intergrowth structures and provides evidence for the presence and nature of internal and outer-surface barriers for molecular diffusion. It has been found that internal-surface barriers originate not only from a 90 degrees mismatch in structure and pore alignment but also from small angle differences of 0.5 degrees-2 degrees for particular crystal morphologies. Furthermore, outer-surface barriers seem to be composed of a silicalite outer crust with a thickness varying from 10 to 200 nm.
authors.affiliation: Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, 3584 CA Utrecht, The Netherlands.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Karwacki
authors.forename: Marianne H F
authors.initials: MH
authors.lastname: Kox
authors.forename: D A Matthijs
authors.initials: DA
authors.lastname: de Winter
authors.forename: Martyn R
authors.initials: MR
authors.lastname: Drury
authors.forename: Johannes D
authors.initials: JD
authors.lastname: Meeldijk
authors.forename: Eli
authors.initials: E
authors.lastname: Stavitski
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schmidt
authors.forename: Machteld
authors.initials: M
authors.lastname: Mertens
authors.forename: Pablo
authors.initials: P
authors.lastname: Cubillas
authors.forename: Neena
authors.initials: N
authors.lastname: John
authors.forename: Ally
authors.initials: A
authors.lastname: Chan
authors.forename: Norma
authors.initials: N
authors.lastname: Kahn
authors.forename: Simon R
authors.initials: SR
authors.lastname: Bare
authors.forename: Michael
authors.initials: M
authors.lastname: Anderson
authors.forename: Jan
authors.initials: J
authors.lastname: Kornatowski
authors.forename: Bert M
authors.initials: BM
authors.lastname: Weckhuysen