TY - JOUR
T1 - Steam-Induced Coarsening of Single-Unit-Cell MFI Zeolite Nanosheets and Its Effect on External Surface Brønsted Acid Catalysis
AU - Guefrachi, Yasmine
AU - Sharma, Geetu
AU - Xu, Dandan
AU - Kumar, Gaurav
AU - Vinter, Katherine P.
AU - Abdelrahman, Omar A.
AU - Li, Xinyu
AU - Alhassan, Saeed
AU - Dauenhauer, Paul J.
AU - Navrotsky, Alexandra
AU - Zhang, Wei
AU - Tsapatsis, Michael
N1 - Publisher Copyright:
© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2020/6/8
Y1 - 2020/6/8
N2 - Commonly used methods to assess crystallinity, micro-/mesoporosity, Brønsted acid site density and distribution (in micro- vs. mesopores), and catalytic activity suggest nearly invariant structure and function for aluminosilicate zeolite MFI two-dimensional nanosheets before and after superheated steam treatment. Yet, pronounced reaction rate decrease for benzyl alcohol alkylation with mesitylene, a reaction that cannot take place in the zeolite micropores, is observed. Transmission electron microscopy images reveal pronounced changes in nanosheet thickness, aspect ratio and roughness indicating that nanosheet coarsening and the associated changes in the external (mesoporous) surface structure are responsible for the changes in the external surface catalytic activity. Superheated steam treatment of hierarchical zeolites can be used to alter nanosheet morphology and regulate external surface catalytic activity while preserving micro- and mesoporosity, and micropore reaction rates.
AB - Commonly used methods to assess crystallinity, micro-/mesoporosity, Brønsted acid site density and distribution (in micro- vs. mesopores), and catalytic activity suggest nearly invariant structure and function for aluminosilicate zeolite MFI two-dimensional nanosheets before and after superheated steam treatment. Yet, pronounced reaction rate decrease for benzyl alcohol alkylation with mesitylene, a reaction that cannot take place in the zeolite micropores, is observed. Transmission electron microscopy images reveal pronounced changes in nanosheet thickness, aspect ratio and roughness indicating that nanosheet coarsening and the associated changes in the external (mesoporous) surface structure are responsible for the changes in the external surface catalytic activity. Superheated steam treatment of hierarchical zeolites can be used to alter nanosheet morphology and regulate external surface catalytic activity while preserving micro- and mesoporosity, and micropore reaction rates.
KW - electron tomography
KW - heterogeneous catalysis
KW - steam treatment
KW - two dimensional materials
KW - zeolites
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U2 - 10.1002/anie.202000395
DO - 10.1002/anie.202000395
M3 - Article
C2 - 32115827
AN - SCOPUS:85082760908
SN - 1433-7851
VL - 59
SP - 9579
EP - 9585
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 24
ER -