Modifying the Catalytic Activity of Zeolite-based Catalysts using Morphology Control
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Date
2021-05
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Publisher
The Ohio State University
Abstract
Porous heterogeneous catalysts are driving an evolution in catalysis because they have
enabled unprecedented catalytic chemistry. However, these porous materials are plagued by
mass transfer limitations wherein the reactants have difficulty diffusing to the catalytically active
sites where the chemistry occurs. As a result, researchers have pushed to create nanoparticle
catalysts like nanozeolites that achieve shorter path lengths from the bulk solution to active
sites at the cost of decreased ease of separation. In contrast, our work seeks to control the
morphology by modifying the growth of specific faces of micron-sized zeolite catalysts. In
this way, we hypothesized that these morphology-controlled zeolites would exhibit shorter path
lengths to active sites and superior catalytic activity while avoiding the separation challenges
posed by nanoparticles.
In this study, we synthesized Sn-substituted zeolite MFI catalysts using an additive known
to increase the plate-like character of MFI crystals, called spermine. Ultimately, we engineered
Sn-MFI catalysts with and without spermine under hydrothermal synthesis conditions. After
synthesis, we characterized the materials' crystallinity using XRD and the porosities using
N2 physisorption. Upon confirmation of successful syntheses, we tested these catalysts in
the epoxide-ring opening reaction of 1,2-epoxyhexane using methanol. We compared the
epoxide reactant conversion of the modified and non-modified zeolite catalysts at various time
points. Thereby, we determined the effects of the crystal modifications on these materials'
catalytic activities. Ultimately, these materials had similar catalytic activities as compared to
non-modified samples.
Description
2nd Place in Engineering: Life and Natural Sciences at the Denman Research Forum
Keywords
Catalysis, Zeolites, Crystal engineering, Reaction engineering, Chemical engineering