Deactivation Mechanism of Potassium on the V2O5/CeO2 Catalysts for SCR Reaction: Acidity, Reducibility and Adsorbed-NOx

A series of V2O5/CeO2 catalysts with different potassium loadings were prepared to investigate alkali deactivations for selective catalytic reduction of NOx with NH3. An alkali poisoning mechanism could be attributed to surface acidity, reducibility, and NOx adsorption/desorption behaviors. The deta...

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Bibliographic Details
Published in:Environmental science & technology 2014-04, Vol.48 (8), p.4515-4520
Main Authors: Peng, Yue, Li, Junhua, Huang, Xu, Li, Xiang, Su, Wenkang, Sun, Xiaoxu, Wang, Dezhi, Hao, Jiming
Format: Article
Language:English
Subjects:
Acids - chemistry
Adsorption
Applied sciences
Atmospheric pollution
Catalysis
Cerium - chemistry
Exact sciences and technology
General processes of purification and dust removal
Nitric Oxide - analysis
Nitrogen Oxides - chemistry
Oxidation-Reduction
Pollution
Potassium - chemistry
Prevention and purification methods
Spectrophotometry, Infrared
Spectrum Analysis, Raman
Surface Properties
Temperature
Vanadium Compounds - chemistry
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Summary:A series of V2O5/CeO2 catalysts with different potassium loadings were prepared to investigate alkali deactivations for selective catalytic reduction of NOx with NH3. An alkali poisoning mechanism could be attributed to surface acidity, reducibility, and NOx adsorption/desorption behaviors. The detailed factors are as follows: (1) decrease of surface acidity suppresses NH3 adsorption by strong bonding of alkali to vanadia (major factor); (2) low reducibility prohibits NH3 activation and NO oxidation by formation bonding of alkali to vanadia and ceria (important factor); (3) active NOx(-) species at low temperature diminish because of coverage of alkali on the surfaces (minor factor); and (4) stable, inactive nitrate species at high temperature increase by generating new basic sites (important factor).
ISSN:0013-936X
1520-5851
DOI:10.1021/es405602a