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Involvement of NCO species in promotion effect of water vapor on propane-SCR over Co-MFI zeolite

Paper ID Volume ID Publish Year Pages File Format Full-Text
48640 46516 2007 8 PDF Available
Title
Involvement of NCO species in promotion effect of water vapor on propane-SCR over Co-MFI zeolite
Abstract

The effect of water vapor on the SCR of NO by propane over Co-MFI zeolite was investigated with respect to behavior of surface NCO species. In the absence of water vapor, the NO conversion at lower temperatures below 648 K decreased with time-on-stream. In the presence of water vapor, on the other hand, the NO conversion was higher than in the absence of water vapor and the catalyst deactivation was not observed. From the measurement of in situ IR spectra, it was found that NCO species accumulates on the catalyst in the absence of water vapor and then leads to deactivation of catalyst. In the presence of water vapor, however, it was found that the NCO species were easily hydrolyzed to ammonia and carbon dioxide, and therefore, the higher SCR activity was obtained. Thus, NCO species, which are known to be an important intermediate to form nitrogen in HC-SCR, could cause self-poisoning in the absence of water vapor.

Keywords
Selective catalytic reduction; Water vapor; Co-MFI; IR spectra; Deactivation
First Page Preview
Involvement of NCO species in promotion effect of water vapor on propane-SCR over Co-MFI zeolite
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 77, Issues 1–2, 30 November 2007, Pages 92–99
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis