Modification of CeO2-ZrO2 catalyst by potassium for NOx-assistedsoot oxidation
Duan Weng , Jia Li , Xiaodong Wu , Zhichun Si
DOI:
Received March 08, 2010,Revised May 04, 2010, Accepted , Available online
Volume 23,2011,Pages 145-150
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Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method. The ageing treatment was performed
in static air at 800°C for 20 hr to evaluate the thermal stability of the catalyst. The catalysts were characterized by X-ray di raction,
BET surface area, oxygen storage capacity, NOx-temperature programmed desorption and soot-temperature programmed oxidation
measurements. By introduction of potassium, the maximum soot oxidation rate temperature (Tm) of the ceria-zirconia based catalyst
decreased from 525 to 428°C in the presence of NO under a loose contact mode. The shift of Tm of the K-modified catalyst after ageing
is only 15°C. The enhanced activity of the aged catalyst mainly lies in the promotional e ect of potassium on the NOx/oxygen storage
capacity as well as the soot-catalyst contact.
