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V2O5-WO3/TiO2-SiO2-SO42− catalysts: Influence of active components and supports on activities in the selective catalytic reduction of NO by NH3 and in the oxidation of SO2

Paper ID Volume ID Publish Year Pages File Format Full-Text
49031 46541 2006 10 PDF Available
Title
V2O5-WO3/TiO2-SiO2-SO42− catalysts: Influence of active components and supports on activities in the selective catalytic reduction of NO by NH3 and in the oxidation of SO2
Abstract

The V2O5-WO3 catalysts loaded on the Ti-rich TiO2-SiO2-SO42− prepared by the coprecipitation method were investigated for the influences of the active components and the supports on the activities in SCR of NO by NH3 and in the oxidation of SO2 in comparison with a commercial V2O5-WO3/TiO2-SO42− catalyst. The physico-chemical properties of the catalysts were characterized by BET, XRD, IR, Raman, NH3-TPD, XPS and acidity measurements. The incorporation of sulfate to TiO2-SiO2 considerably increases the acidity of TiO2-SiO2, especially Brønsted acidity of the corresponding catalyst, resulting in the remarkable increase of the SCR activity and simultaneously, the addition of WO3 significantly enhances the SCR activity. The SCR activity changes depending on the calcination temperature of TiO2-SiO2-SO42−, which influences its acidity, surface area and titania crystallinity. The higher SCR activity was observed at high vanadia loadings above 2 wt.% as compared with the V2O5-WO3/TiO2-SO42− catalyst. This seems to be due to the fact that polymeric vanadates on the catalyst, which cause the oxidation of NH3 to N2O, are almost absent as evidenced by Raman analysis. The SO2 oxidation activity is increased by elevating the calcination temperature of TiO2-SiO2-SO42−, which shifts the oxidation state of vanadium species to the higher state, and the activity is slightly enhanced by WO3 but not changed by sulfate. The tendency of the increase in the SO2 oxidation activity with increasing V2O5 loadings is significantly smaller than the V2O5-WO3/TiO2-SO42− catalyst. This was attributed to the lower oxidation state of vanadium species, almost the absence of polymeric vanadates responsible for the SO2 oxidation and also a more strongly inhibiting effect of ammonia on the oxidation of SO2.

Keywords
SCR; SO2 oxidation; Sulfate; TiO2-SiO2-SO42−; V2O5-WO3/TiO2-SiO2-SO42−; Acidity
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V2O5-WO3/TiO2-SiO2-SO42− catalysts: Influence of active components and supports on activities in the selective catalytic reduction of NO by NH3 and in the oxidation of SO2
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 63, Issues 1–2, 22 March 2006, Pages 104–113
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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