Title of article :
In2O3/Al2O3 Catalysts for NOx Reduction in Lean Condition
Author/Authors :
Paul W. Park، نويسنده , , Christie S. Ragle، نويسنده , , Carrie L. Boyer، نويسنده , , M.Lou Balmer، نويسنده , , Mark Engelhard، نويسنده , , David McCready، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2002
Pages :
9
From page :
97
To page :
105
Abstract :
The lean NOx performance and catalytic properties of In2O3/Al2O3 catalysts were investigated. High lean NOx activity was observed when propene was used as a reductant in the presence of 9% O2 and 7% H2O at a space velocity of 30,000 h−1. The optimum lean NOx activity of In2O3/Al2O3 catalysts was observed at a loading of 2.5 wt% indium on γ-Al2O3 which was prepared by a sol–gel technique (230 m2/g). When propane was used as a reductant, the In2O3/Al2O3 catalyst did not promote NOx reduction compared to the alumina substrate. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and temperature-programmed reduction (TPR) have been used to characterize a series of In2O3/Al2O3 catalysts to increase understanding of the surface structure of indium oxide species on the alumina support. The XRD data indicated that crystalline In2O3 was present at In2O3 loadings >5 wt% and the quantity of the crystalline phase increased as a function of indium loading. XPS results suggested that indium oxide existed as a well-dispersed phase up to 10 wt% indium. The well-dispersed or reducible indium oxide species below 400°C in TPR experiments were assigned as the sites which activate propene to oxygenated hydrocarbons such as acetaldehyde and acrolein. Alumina sites readily utilize the oxygenated hydrocarbons to reduce NOx. A bifunction mechanism was proposed to explain high NOx reduction over In2O3/Al2O3 catalysts.
Journal title :
Journal of Catalysis
Serial Year :
2002
Journal title :
Journal of Catalysis
Record number :
1222416
Link To Document :
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