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Confirmation of isolated Cu 2+ ions in SSZ-13 zeolite as active sites in NH 3-selective catalytic reduction

Deka, U., Juhin, A., Eilertsen, E.A., Emerich, H., Green, M.A., Korhonen, S.T., Weckhuysen, B.M., Beale, A.M. (2012) Confirmation of isolated Cu 2+ ions in SSZ-13 zeolite as active sites in NH 3-selective catalytic reduction. Journal of Physical Chemistry C, 116 (7). pp. 4809-4818. ISSN 19327447 (ISSN). (doi:10.1021/jp212450d) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Abstract

NH 3-Selective Catalytic Reduction (NH 3-SCR) is a widely used technology for NO x reduction in the emission control systems of heavy duty diesel vehicles. Copper-based ion exchanged zeolites and in particular Cu-SSZ-13 (CHA framework) catalysts show both exceptional activity and hydrothermal stability for this reaction. In this work, we have studied the origin of the SCR activity of Cu-SSZ-13 as evidenced from a combination of synchrotron-based and laboratory techniques. Synchrotron-based in situ XAFS/XRD measurements were used to provide complementary information on the local copper environment under realistic NH 3-SCR conditions. Crucial then to the catalytic activity of Cu-SSZ-13 is the local environment of the copper species, particularly in the zeolite. Cu-SSZ-13 contains mononuclear Cu 2+ species, located in the face of the double-6-ring subunit of the zeolite after calcination where it remains under reaction conditions. At lower temperatures (with low activity), XAFS and XRD data revealed a conformational change in the local geometry of the copper from a planar form toward a distorted tetrahedron as a result of a preferential interaction with NH 3. This process appears necessary for activity, but results in a stymieing of activity at low temperatures. At higher temperatures, the Cu 2+ possess a local coordination state akin to that seen after calcination. © 2012 American Chemical Society.

Item Type: Article
DOI/Identification number: 10.1021/jp212450d
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - J. Phys. Chem. C [Field not mapped to EPrints] AD - Materials Innovation Institute (M2i), Mekelweg 2, 2628 CD Delft, Netherlands [Field not mapped to EPrints] AD - Inorganic Chemistry and Catalysis Group, Debye Institute of Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CA Utrecht, Netherlands [Field not mapped to EPrints] AD - Institut de Minéralogie et de Physique des Milieux Condensés, CNRS, Université Pierre et Marie Curie, Case courier 115, 4 place, Jussieu 75252, Paris Cedex 05, France [Field not mapped to EPrints] AD - SMN/INGAP, Department of Chemistry, University of Oslo, Sem Selands vei 26, 0315 Oslo, Norway [Field not mapped to EPrints] AD - Swiss Norwegian Beamline (SNBL, BM01), ESRF, BP 220, F-38043 Grenoble, France [Field not mapped to EPrints] AD - Beamline BT1, NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20878, United States [Field not mapped to EPrints] AD - Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, United States [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: Active site, Conformational change, Copper environments, Copper-based, Heavy duty diesel vehicles, Higher temperatures, Hydrothermal stabilities, In-situ, Ion exchanged zeolites, Laboratory techniques, Local coordination, Local environments, Local geometry, Low temperatures, Preferential interaction, Reaction conditions, XAFS, XRD, Calcination, Catalyst activity, Copper, Emission control, Selective catalytic reduction
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Q Science > QD Chemistry > QD478 Solid State Chemistry
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Giles Tarver
Date Deposited: 14 Oct 2015 11:31 UTC
Last Modified: 29 May 2019 16:08 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/50970 (The current URI for this page, for reference purposes)
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