Morphology-dependent zeolite intergrowth structures leading to distinct internal and outer-surface molecular diffusion barriers.
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.
Karwacki
Lukasz
L
Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, 3584 CA Utrecht, The Netherlands.
Kox
Marianne H F
MH
de Winter
D A Matthijs
DA
Drury
Martyn R
MR
Meeldijk
Johannes D
JD
Stavitski
Eli
E
Schmidt
Wolfgang
W
Mertens
Machteld
M
Cubillas
Pablo
P
John
Neena
N
Chan
Ally
A
Kahn
Norma
N
Bare
Simon R
SR
Anderson
Michael
M
Kornatowski
Jan
J
Weckhuysen
Bert M
BM