X-Ray Imaging of SAPO-34 Molecular Sieves at the Nanoscale: Influence of Steaming on the Methanol-to-Hydrocarbons Reaction
Please use this identifier to cite or link to this item:
http://hdl.handle.net/10045/39544
Title: | X-Ray Imaging of SAPO-34 Molecular Sieves at the Nanoscale: Influence of Steaming on the Methanol-to-Hydrocarbons Reaction |
---|---|
Authors: | Aramburo, Luis R. | Ruiz Martínez, Javier | Sommer, Linn | Arstad, Bjørnar | Buitrago Sierra, Robison | Sepúlveda-Escribano, Antonio | Zandbergen, Henny W. | Olsbye, Unni | Groot, Frank M.F. de | Weckhuysen, Bert M. |
Research Group/s: | Materiales Avanzados |
Center, Department or Service: | Universidad de Alicante. Departamento de Química Inorgánica | Universidad de Alicante. Instituto Universitario de Materiales |
Keywords: | Carbon | Hydrocarbons | Hydrothermal treatment | Molecular sieves | X-ray absorption |
Knowledge Area: | Química Inorgánica |
Issue Date: | Jun-2013 |
Publisher: | Wiley-VCH Verlag GmbH & Co. KGaA |
Citation: | ChemCatChem. 2013, 5(6): 1386-1394. doi:10.1002/cctc.201200670 |
Abstract: | The effect of a severe steaming treatment on the physicochemical properties and catalytic performance of H-SAPO-34 molecular sieves during the methanol-to-hydrocarbons (MTH) reaction has been investigated with a combination of scanning transmission X-ray microscopy (STXM), catalytic testing, and bulk characterization techniques, including ammonia temperature programmed desorption and 27Al and 29Si magic angle spinning nuclear magnetic resonance. For this purpose, two samples, namely a calcined and a steamed H-SAPO-34 catalyst powder, have been compared. It has been found that calcined H-SAPO-34 displays a high selectivity towards light olefins, yet shows a poor stability as compared to a zeolite H-ZSM-5 catalyst. Moreover, in situ STXM at the carbon K-edge during the MTH reaction allows construction of nanoscale chemical maps of the hydrocarbon species formed within the H-SAPO-34 aggregates as a function of reaction time and steam post-treatment. It was found that there is an initial preferential formation of coke precursor species within the core of the H-SAPO-34 aggregates. For longer times on stream the formation of the coke precursor species is extended to the outer regions, progressively filling the entire H-SAPO-34 catalyst particle. In contrast, the hydrothermally treated H-SAPO-34 showed similar reaction selectivity, but decreased activity and catalyst stability with respect to its calcined counterpart. These variations in MTH performance are related to a faster and more homogeneous formation of coke precursor species filling up the entire steamed H-SAPO-34 catalyst particle. Finally, the chemical imaging capabilities of the STXM method at the Al and Si K-edge are illustrated by visualizing the silicon islands at the nanoscale before and after steaming H-SAPO-34. |
URI: | http://hdl.handle.net/10045/39544 |
ISSN: | 1867-3880 (Print) | 1867-3899 (Online) |
DOI: | 10.1002/cctc.201200670 |
Language: | eng |
Type: | info:eu-repo/semantics/article |
Rights: | © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim |
Peer Review: | si |
Publisher version: | http://dx.doi.org/10.1002/cctc.201200670 |
Appears in Collections: | INV - LMA - Artículos de Revistas |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
2013_Aramburo_etal_ChemCatChem_final.pdf | Versión final (acceso restringido) | 1,57 MB | Adobe PDF | Open Request a copy |
Items in RUA are protected by copyright, with all rights reserved, unless otherwise indicated.