Catalytic Characterization of Hierarchical Meso-/microporous Lamellar Zeolite Catalysts

2013 Spring Symposium

 
Dongxia Liu
Department of Chemical and Biomolecular Engineering
University of Maryland
College Park, MD 20742
liud@umd.edu

 
Abstract – The meso/micro-zeolites couple the catalytic features of micropores and the improved access and transport consequence of mesopores in a single material, possessing the capacity of processing large molecules. The synthesis and catalytic behavior investigation of meso/micro-zeolites has become the subject of intense research. This talk highlights the synthesis and catalytic characterizations of three emerging acidic meso-/micro-porous lamellar zeolite materials (self-pillared MFI, pillared MFI, multilamellar MFI), with a focus on their catalytic behavior investigations using ethanol dehydration, monomolecular conversion of propane and isobutane, and alkylation of mesitylene with benzyl alcohol as probe reactions. The rate and apparent activation energy of the catalytic ethanol and small alkane probe reactions in zeolites possessing dual micro- and meso-porosity was comparable to conventional microporous MFI materials, implying that the catalytic behavior of Brønsted acid sites in materials with dual meso-/micro-porosity is preferentially dominated by the microporous environment possibly because it provides a better fit for adsorption of small alkane or alcohol reactant molecules. The apparent rate constant of the catalytic alkylation of mesitylene with benzyl alcohol in meso/micro-porous zeolites was higher than that of their microporous analogues, revealing the role of the mesoporosity in space-demanding catalytic reactions. A mathematical model accounts for the external reaction, internal reaction, and diffusion developed to understand the catalytic behaviors of these catalysts.
 

Dongxia Liu

Dongxia Liu

Biography – Dongxia Liu received her Ph.D. in chemical engineering from University of Rochester in 2009. Her PhD work focused on Development of Novel Electrolyte Membranes for Intermediate Temperature Fuel Cells. After graduation, she did two year of post-doctorate in University of Minnesota with Prof. Michael Tsapatsis and Prof. Aditya Bhan, focusing on the synthesis and characterization of novel meso-/microporous zeolite catalysts. In 2012, Dongxia Liu joined the department of chemical and biomolecular engineering at the University of Maryland as an assistant professor. Her research interests lie in the synthesis, characterization and evaluation of novel hierarchical meso-/microporous materials, which are used as efficient catalysts in diffusion constrained reactions and as selective membranes for water purification applications.