Steam-Induced Coarsening of Single-Unit-Cell MFI Zeolite Nanosheets and Its Effect on External Surface Brønsted Acid Catalysis

Yasmine Guefrachi, Geetu Sharma, Dandan Xu, Gaurav Kumar, Katherine P. Vinter, Omar A. Abdelrahman, Xinyu Li, Saeed Alhassan, Paul J. Dauenhauer, Alexandra Navrotsky, Wei Zhang, Michael Tsapatsis

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)9579-9585
Number of pages7
JournalAngewandte Chemie - International Edition
Volume59
Issue number24
DOIs
StatePublished - Jun 8 2020
Externally publishedYes

Keywords

  • electron tomography
  • heterogeneous catalysis
  • steam treatment
  • two dimensional materials
  • zeolites

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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