Influence of Co or Ce addition on the NOx storage and sulfur-resistance performance of the lean-burn NOx trap catalyst Pt/K/TiO2-ZrO2

J Hazard Mater. 2009 Oct 15;170(1):118-26. doi: 10.1016/j.jhazmat.2009.04.125. Epub 2009 May 5.

Abstract

The Pt/K/TiO(2)-ZrO(2) catalysts promoted by Co or Ce were prepared by successive impregnation or mechanically mixing method. The influence of Co or Ce addition on the NOx storage and sulfur-resistance performance of the catalyst was investigated carefully. The techniques of XRD, FT-IR, in-situ DRIFTS, H(2)-TPR and XPS were employed for catalyst characterization. The Co or Ce addition can greatly improve the NOx storage capacity of Pt/K/TiO(2)-ZrO(2) due to the enhanced oxidation ability and the release of more K sites. Ce addition induces higher K/Ti atomic ratio and larger NOx storage capacity as compared with Co addition. After sulfation and regeneration, the promoted catalysts shows more or less decreased NSC than Pt/K/TiO(2)-ZrO(2) due to the formation of more sulfates, especially for the Co-promoted catalysts, which possess better oxidation ability and facilitate the formation of large sulfates. The effect of Ce addition on Pt/K/TiO(2)-ZrO(2) largely depends on the addition mode. The high oxidation ability and the high K/Ti ratio of the mechanically prepared Ce-promoted catalyst make it still possess considerable NOx storage capacity (NSC) of 142 micromol/g after sulfation and regeneration. With the decrease of sulfur content in fuels, the Co- and Ce-promoted catalysts possessing large NOx storage capacity, will be applicable to the purification of lean-burn NOx.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Cerium
  • Cobalt
  • Energy-Generating Resources*
  • Nitrogen Oxides*
  • Platinum
  • Potassium
  • Sulfur
  • Titanium
  • Zirconium

Substances

  • Nitrogen Oxides
  • titanium dioxide
  • Cerium
  • Cobalt
  • Platinum
  • Sulfur
  • Zirconium
  • Titanium
  • Potassium
  • zirconium oxide