Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (02): 156-160.doi: 10.3866/PKU.WHXB20050209

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The Structures of VOx/ZrO2 and K-VOx/ZrO2 Catalysts and Their Catalytic Performances for Diesel Soot Oxidation

LIU Jian;ZHAO Zhen;XU Chun-Ming   

  1. State Key Laboratory of Heavy Oil Processing, University of Petroleum, Beijing 102249
  • Received:2004-07-01 Revised:2004-09-05 Published:2005-02-15
  • Contact: ZHAO Zhen

Abstract: Two systems of VOx/ZrO2 and K-VOx/ZrO2 catalysts with different compositions were prepared by incipient-wetness impregnation method. The catalytic performances of these catalysts for diesel soot catalytic oxidation were investigated with temperature-programmed oxidation reaction (TPO). The results showed that the catalytic properties of the VOx/ZrO2 catalysts depend on the VOx concentration. The VOx/ZrO2 catalyst has the best activity for soot oxidation when nV∶nZr is 4:100.The VOx/ZrO2 and K-VOx/ZrO2 catalysts were characterized by FT-IR and UV-Vis. The results revealed that the highest concentration of polymerized vanadyl species presented on the surfaces of the VOx/ZrO2 catalysts when nV∶nZr =4∶100.The polymerized vanadyl can lower the oxidation temperature of diesel soot because they have very strong redox abilities. The addition of potassium to VOx/ZrO2 catalysts can improve the catalytic activities for soot oxidation apparently. When nK∶nV∶nZr =1∶4∶100,the catalyst K-VOx/ZrO2 has the best activity for soot oxidation, i.e., the lowest reaction temperature. But the catalytic activity of the K- VOx/ZrO2 catalysts decreased when nK∶nV > 1∶4,which is due to the formation of KVO3 whose surface atoms mobility is much weaker than that of polymeric VOx specie and dispersed potassium oxide.

Key words: VOx, ZrO2, Catalyst, Soot, Catalytic oxidation