Title of article :
Mechanistic study of the influence of surface acidity on lean NO2 reduction by propane in HZSM-5
Author/Authors :
Hanna H?relind Ingelsten، نويسنده , , Dongmei Zhao، نويسنده , , Anders Palmqvist، نويسنده , , Magnus Skoglundh، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2005
Pages :
12
From page :
68
To page :
79
Abstract :
This study focuses on the mechanism of lean NOx reduction by propane, over acidic zeolites (HZSM-5), and the influence of surface acidity. In situ FTIR measurements of ammonia adsorption indicate a higher number of Brønsted acid sites for a sample with a low SiO2/Al2O3 ratio. The activity for NOx reduction and the selectivity for N2 formation correlate well with the Brønsted acidity. Step-response experiments with NO2 and propane show the formation of surface-bound NO+, isocyanate, unsaturated hydrocarbons, and amine species. Formation of the latter two seems to be closely related to the Brønsted acidity. In the NO2 reaction with propane, the NO+ species seem to play a vital role, probably reacting with carbenium ions (from propane cracking) to form isocyanates, which may be hydrolysed to amine species. Step-response experiments with isopropylamine and NO2 indicate a fast reaction, where the amine and NO+ species react over Brønsted acid sites. Hence, amine species are possible reaction intermediates in the lean reduction of NO2 by saturated hydrocarbons, such as propane, over HZSM-5.
Keywords :
6-Dimethyl-2-thiomethylpyrimidine , UL-TS-1 , Ti-SBA-15 , Ionic liquid , heterogeneous , 4 , Sulfoxidation
Journal title :
Journal of Catalysis
Serial Year :
2005
Journal title :
Journal of Catalysis
Record number :
1223834
Link To Document :
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