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K-supported catalysts for diesel soot combustion: Making a balance between activity and stability

Paper ID Volume ID Publish Year Pages File Format Full-Text
53312 46962 2016 9 PDF Available
Title
K-supported catalysts for diesel soot combustion: Making a balance between activity and stability
Abstract

•Activity and stability are two sides of the coin for K-containing catalysts.•The active sites are the free K species.•The immobilized K+ ions in the lattice can seriously reduce the activity.•Balancing of activity and stability was realized by using the tunneled cryptomelane.

Two typical K-supported oxides (K/Al2O3 and K/TiO2) were selected as catalysts for diesel soot combustion in order to evaluate the relationship between activity and stability. The surface species were first characterized by X-ray powder diffraction (XRD), X-ray absorption fine-structure (XAFS), infrared analysis (IR), X-ray photoelectron spectroscopy (XPS), in situ IR of CO2 adsorption and temperature-programmed desorption of CO2 (CO2-TPD). Then the activity was studied by temperature-programmed oxidation (TPO), temperature-programmed reduction with soot (Soot-TPR) and in situ IR of soot combustion reactions. Lastly, the stability of the catalyst was checked by washing with water and analysis for K. This showed that K/TiO2 displayed negligible activity due to the immobilization of K+ ions in TiO2 to form K2Ti6O13. However, K/Al2O3 exhibited superior activity owing to the presence of active free K+ ions on the surface. The downside is the leaching of K+ ions into the effluent containing some water vapor, resulting in its poor stability – the other side of the coin for the highly active free K species. One of the suggested strategies for making a balance between activity and stability is encapsulating active K species in the channel of the catalyst as demonstrated by the tunneled cryptomelane.

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Keywords
Soot combustion; Free K+ ions; Activity; Stability; Cryptomelane
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K-supported catalysts for diesel soot combustion: Making a balance between activity and stability
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 264, 15 April 2016, Pages 171–179
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
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
Online Support
Any Questions? feel free to contact us