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Characterization of Active Species in Cu-Beta Zeolite by Temperature-Programmed Reduction Mass Spectrometry (TPR-MS)

J. H. Li ; Norman Wilken (Institutionen för kemi- och bioteknik, Kemisk reaktionsteknik ; Kompetenscentrum katalys (KCK)) ; K. Kamasamudram ; N. W. Currier ; Louise Olsson (Institutionen för kemi- och bioteknik, Kemisk reaktionsteknik ; Kompetenscentrum katalys (KCK)) ; A. Yezerets
Topics in Catalysis (1022-5528). Vol. 56 (2013), 1-8, p. 201-204.
[Artikel, refereegranskad vetenskaplig]

The number and type of copper species present in an under-exchanged Cu-Beta zeolite catalyst were characterized using temperature-programmed reduction mass spectrometry (TPR-MS). Both H-2 consumption and H2O evolution were tracked, yielding additional insights into the nature of Cu species. Prior to the TPR-MS tests, catalyst samples were subjected to various high- temperature aging treatments in the presence of O-2 in He, in order to assist with interrogating and resolving different types of sites. Absence of reducible species in the precursor material was confirmed by subjecting the H-form of the same zeolite to the TPR. Upon aging at temperatures below 700 A degrees C, the TPR pattern showed several distinct peaks of different intensities. Aging at 800 A degrees C led to shifting and broadening of these H-2 consumption peaks, as well as to some reduction of the integral amount of the reducible sites. The 900 A degrees C exposure resulted in a drastic change of the TPR pattern, with several new well-resolved H-2 consumption peaks, indicative of drastic changes in the catalyst structure. The integral amount of H-2 consumed quantitatively matched the amount of Cu species present in the catalyst, assuming the stoichiometry. The combination of experimental findings in this work lends support to a hypothesis that different TPR peaks are indicative of different types of sites rather than of step-wise reduction of copper species.

Nyckelord: Cu-zeolite, Beta-zeolite, SCR, Temperature-programmed reduction

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Denna post skapades 2013-06-10. Senast ändrad 2013-06-10.
CPL Pubid: 178104


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Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Kemisk reaktionsteknik (2005-2014)
Kompetenscentrum katalys (KCK)


Fysikalisk kemi

Chalmers infrastruktur

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