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

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.