title: 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.
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.
authors.affiliation: Tianjin Key Laboratory of Applied Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Zou
authors.forename: Ming
authors.initials: M
authors.lastname: Meng
authors.forename: Noritatsu
authors.initials: N
authors.lastname: Tsubaki
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: He
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Xin-Gang
authors.initials: XG
authors.lastname: Li
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Zhou
mesh_terms: D002384:Catalysis; D002563:Cerium; D003035:Cobalt; D004736:Energy-Generating Resources; D009589:Nitrogen Oxides; D010984:Platinum; D011188:Potassium; D013455:Sulfur; D014025:Titanium; D015040:Zirconium
chemical_list: D009589:Nitrogen Oxides; C009495:titanium dioxide; D002563:Cerium; D003035:Cobalt; D010984:Platinum; D013455:Sulfur; D015040:Zirconium; D014025:Titanium; D011188:Potassium; C028541:zirconium oxide