含贵金属的BaZrO_3储存NO_x催化剂结构及性能研究  

Study of Structure and Property for the NO_x Storage Catalyst BaZrO_3 Containing Noble Metal

作　　者：高爱梅[1] 林培琰[1] 屠兢[1] 孟明[1] 李全新[1] 

机构地区：[1]中国科学技术大学化学物理系,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2004年第4期485-488,共4页化学物理学报（英文）

基　　金：Projectsupportedbythe"P .R .Program"ofChineseAcademyofSciencesandtheExcellentYoungTeachersProgramofMOE P .R .C .

摘　　要：用溶胶 凝胶法制备了钙钛矿型BaZrO3催化剂 ,再用等量浸渍法制备了Rh/BaZrO3样品 ,并制备了Rh/BaZrO3/γ Al2 O3和Pt/BaZrO3/γ Al2 O3催化剂 .对它们的NOx 储存量 (NSC)及其抗硫性能进行了测试 ,并用X射线衍射 (XRD)、X光电子能谱 (XPS)和傅里叶变换红外光谱 (FT IR)等方法研究了它们的结构及其对性能的影响 .结果表明 ,BaZrO3催化剂具有良好的储氮及抗硫性能 ,直接添加贵金属到BaZrO3中会使NSC降低 ,而混合γ Al2 O3后添加Pt或Rh可以大大提高NSC ,上述两种方式引入贵金属都能改善催化剂的抗硫性能 .A series of perovskite type BaZrO 3 catalysts are prepared by the sol gel method. Their NO x storage capacity (NSC) and the resistance of SO 2 poison are measured. XRD, XPS and FT IR techniques are also used to characterize their structures and the influence of the structures on performance. The results indicate that, after calcination at 750 and 900 ℃, the Ba and Zr species mainly exist in the form of perovskite BaZrO 3 phase, and the BaCO 3 and ZrO 2 phases also exist. The presence of bulk nitrate is shown by XRD and FT IR after BaZrO 3 absorbing NO x . The Rh/BaZrO 3 is prepared by doping 0.5%Rh on the BaZrO 3 with the impregnation method. It is found that the Rh mainly deposits on the surface of catalyst. However, the noble metals 0.5% Rh or Pt well disperse on the surface of the sample after the BaZrO 3 is mixed with γ Al 2O 3 in equal weight proportion. The structure of perovskite BaZrO 3 may be partly broken after doping Rh or Pt, because of the reduction by hydrogen in the process of preparing samples, and then some ZrO 2 is enriched on the surface. The BaZrO 3 catalysts possess high NSC and high resistance ability of SO 2 poison. The NSC of Rh/BaZrO 3 decreases compared to that of BaZrO 3. However, the NSC of the samples Pt/BaZrO 3/γ Al 2O 3 and Rh/BaZrO 3/γ Al 2O 3 increases by 78% and 15% respectively. It is noticed that the NSC enhances for all the samples containing noble metal Pt or Rh duing the 0.01%SO 2 mixed with the NO and O 2. It implies that the NO oxidation is improved by SO 2.

关 键 词：钡锆钙钛矿相 贵金属铂或铑 Γ-氧化铝 NOx 储存容量 抗硫性能 

分 类 号：O643[理学—物理化学]