催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (8): 730-736.

• 研究论文 • 上一篇    下一篇

前驱体对Ba/(Pt/γ-Al2O3)催化剂NOx存储性能的影响

王晖,段连运,谢有畅   

  1. 北京大学化学与分子工程学院分子动态与稳态结构国家重点实验室, 北京分子科学国家实验室, 北京 100871
  • 收稿日期:2007-08-25 出版日期:2007-08-25 发布日期:2011-08-19

Influence of Ba Precursors on NOx Storage Property of Ba/(Pt/γ-Al2O3) Catalysts

WANG Hui, DUAN Lianyun*, XIE Youchang   

  1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
  • Received:2007-08-25 Online:2007-08-25 Published:2011-08-19

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758

被引次数

2

摘要： 分别以Ba(NO3)2和Ba(CH3COO)2为Ba的前驱体,利用浸渍法制备了两个系列不同Ba含量的NOx存储还原催化剂Ba/(Pt/γ-Al2O3). 采用X射线衍射、X射线光电子能谱、程序升温反应脱附和差热-热重等分析技术对样品进行了表征,并考察了催化剂的NOx存储性能. 结果表明,不同前驱体在Pt/γ-Al2O3载体表面的分散能力不同. 前驱体为Ba(NO3)2时, Ba的分散阈值为0.047 g/g (Ba/(Pt/γ-Al2O3)质量比), 而前驱体为Ba(CH3COO)2时, Ba的分散阈值为0.149 g/g (Ba/(Pt/γ-Al2O3)质量比). 经高温焙烧后,前驱体的分散容量决定催化剂中Ba物种的分散容量. 在NOx存储性能评价实验中,以Ba(CH3COO)2为前驱体时,催化剂的NOx等温吸附穿透时间最长为23 min, 而以Ba(NO3)2为前驱体时,具有相同Ba含量的催化剂的穿透时间为13 min. 因此,在制备NOx存储还原催化剂时,选择易分散的前驱体Ba(CH3COO)2可以获得较高的NOx存储活性的催化剂.

关键词: 硝酸钡, 醋酸钡, 氮氧化物, 存储, 单层分散, 稀燃

Abstract: NOx storage-reduction catalysts, Ba/(Pt/γ-Al2O3), were prepared by the impregnation method using Ba(NO3)2 and Ba(CH3COO)2 as the barium precursors. Characterization studies of the catalysts were performed by means ofX-raydiffraction,X-rayphotoelectron spectroscopy, temperature-programmed reaction desorption, and differential thermal analysis-thermogravimetry. The results indicate that the dispersion threshold of Ba(NO3)2 is 0.047 g/g (Ba/(Pt/γ-Al2O3) mass ratio), which is only about 1/3 of that ofBa(CH3COO)2. After the calcination treatment, the threshold of barium for the catalyst using Ba(CH3COO)2 as the precursor is larger than that using Ba(NO3)2 as the precursor. As a result, the Ba/(Pt/γ-Al2O3) catalyst prepared from Ba(CH3COO)2 has a higher NOx storage capacity than the catalyst prepared from Ba(NO3)2.

Key words: barium nitrate, barium acetate, nitrogen oxide, storage, monolayer dispersion, lean-burn