Characterization of Active Species in Cu-Beta Zeolite by Temperature-Programmed Reduction Mass Spectrometry (TPR-MS)
Artikel i vetenskaplig tidskrift, 2013

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.

Cu-zeolite

Beta-zeolite

SCR

Temperature-programmed reduction

Författare

J. H. Li

Cummins Inc.

Norman Wilken

Chalmers, Kemi- och bioteknik, Kemisk reaktionsteknik

Kompetenscentrum katalys (KCK)

K. Kamasamudram

Cummins Inc.

N. W. Currier

Cummins Inc.

Louise Olsson

Kompetenscentrum katalys (KCK)

Chalmers, Kemi- och bioteknik, Kemisk reaktionsteknik

A. Yezerets

Cummins Inc.

Topics in Catalysis

1022-5528 (ISSN) 1572-9028 (eISSN)

Vol. 56 201-204

Styrkeområden

Transport

Ämneskategorier

Fysikalisk kemi

DOI

10.1007/s11244-013-9952-1