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Proceedings Paper

In-situ imaging of reacting single-particle zeolites by non-linear optical microscopy
Author(s): Paul J. Wrzesinski; Mikhail N. Slipchenko; Taslima A. Zaman; Robert M. Rioux; James R. Gord; Sukesh Roy
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Paper Abstract

Zeolite catalysis has been exploited by the petrochemical industry since the 1940’s for catalytic cracking reactions of long chain hydrocarbons. The selectivity of zeolites strongly depends on a pore size, which is controlled by the chosen structure-directing agent (SDA) and by the SDA decomposition/removal process. Although zeolites are composed of micron-sized crystals, studies of zeolite materials typically focus on bulk (i.e., ensemble) measurements to elucidate structure-function information or to optimize catalysts and/or process parameters. To examine these phenomena on the microscale, non-linear optical microscopy is used to provide real-time imaging of chemical reactions in zeolites at temperatures exceeding 400°C. The template decomposition mechanism is studied, as elucidation of the mechanism is critical to understanding the relationship between the decomposition chemistry and the nanoscale features of the zeolite (topology, Si/Al ratio, added dopants). Forward stimulated Raman scattering (SRS), forward coherent anti-Stokes Raman scattering (CARS) and epi two-photon fluorescence (TPF) modalities are acquired simultaneously providing video-rate structural and chemical information. A high-temperature cell with gas inlet system is used for the study of reactions under various temperatures and gas environments. Examining the decomposition process with single-particle resolution enables access to ensemble-level and spatially-resolved behavior. Parallel experiments on bulk zeolite powders are conducted to enable comparison of ensemble and single-particle behavior during template decomposition. Our multi-technique approach has high potential for gaining insight into the link between nanoscale structure and catalytic activity and selectivity of zeolitic materials.

Paper Details

Date Published: 9 March 2015
PDF: 6 pages
Proc. SPIE 9355, Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XV, 935506 (9 March 2015); doi: 10.1117/12.2080339
Show Author Affiliations
Paul J. Wrzesinski, Spectral Energies, LLC (United States)
Mikhail N. Slipchenko, Spectral Energies, LLC (United States)
Taslima A. Zaman, The Pennsylvania State Univ. (United States)
Robert M. Rioux, The Pennsylvania State Univ. (United States)
James R. Gord, Air Force Research Lab. (United States)
Sukesh Roy, Spectral Energies, LLC (United States)

Published in SPIE Proceedings Vol. 9355:
Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XV
Alexander Heisterkamp; Peter R. Herman; Michel Meunier; Stefan Nolte, Editor(s)

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