高等学校化学学报

高等学校化学学报 ›› 2003, Vol. 24 ›› Issue (11): 2060.

• 论文 • 上一篇    下一篇

富氧条件下贵金属催化剂上丙烯选择性还原NO研究

李俊华, 郝吉明, 傅立新, 朱天乐, 程玲琳   

  1. 清华大学环境科学与工程系, 北京 100084
  • 收稿日期:2002-09-28 出版日期:2003-11-24 发布日期:2003-11-24
  • 通讯作者: 李俊华(1970年出生),男,博士,副研究员,从事环境催化与大气污染控制研究.E-mail:lijunhua@tsinghua.org.cn E-mail:lijunhua@tsinghua.org.cn
  • 基金资助:

    国家“八六三”计划(批准号:2001AA643030)资助

Selective Catalytic Reduction of Nitrogen Oxide by Propene over Noble CatalystSIn the Pressence of Exess Oxygen

LI Jun-Hua, HAO Ji-Ming, FU Li-Xin, ZHU Tian-Le, CHEN Ling-Lin   

  1. Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China
  • Received:2002-09-28 Online:2003-11-24 Published:2003-11-24

被引次数

49

摘要： 用溶胶-凝胶(Sol-gel)法制备了以γ-Al2O3为载体,以Pt,Pd和Rh等为活性组分的单组分及双组分催化剂,在稀燃汽油机条件下评价了丙烯对NO的选择性催化还原活性.结果表明,在单组分催化剂中,催化剂的活性及顺序为Rh(73%)>Pt(65%)>Pd(47%),最高活性对应的温度分别为Pt(225℃),Pd(275℃)和Rh(375℃),N2选择性顺序为Rh,Pd(>80%)>Pt(48%),氧化性顺序为Pt>Rh>Pd.Sol-gel制备的双组分催化剂中的不同贵金属活性位具有一定的协同效应,可明显拓宽活性温度范围,其中以Pt-Rh组合活性最好.Rh/Al2O3和Pt/Al2O3两种催化剂分层有序填装时,可提高C3H6的利用率,在200～450℃范围内,可有效地催化净化NO.

关键词: 稀燃车尾气, 贵金属催化剂, NO还原, 选择性催化还原, 协同效应

Abstract: The selective catalytic reduction(SCR) of nitrogen oxides by hydrocarbonSIs considered to be one of the most efficient ways to remove NO from lean burn automobile exhaust.The single noble metals Pt, Pd and Rh catalysts and two catalytic active components(Pt-Pd, Pt-Rh, Pd-Rh) based on the γ-alumina were prepared by the sol-gel and the selective catalytic reduction activity of NO with propene(C3H6) as reductant in the presence of excess oxygen waSInvestigated in a fixed-bed microreactor.The results show that the order of activity for NO conversion and their optimal temperature is Rh (73%, 375℃)>Pt(65%, 225℃)>Pd(47%, 275℃), Pd and Rh have a higher activity for NO reduction to N2than that of Pt, while Pt-Al2O3has a high activity for NO oxidation to NO2, but the lowest selectivity for NO to N2.The temperature ranges of the two catalytic active components catalysts for NO reduction have been broaden in comparison with the different temperature ranges of single catalytic component catalyst.The combined Pt-Rh catalyst is the most active among them.In different combination of Pt-Al2O3and Rh-Al2O3with physically mixed catalysts and packed with two-stage catalysts, it is found that the two-stage catalysts have a better activity than that of the other combinationSIn a wide temperature range(200-450 ℃) because the reductant C3H6can be used efficiently, and this combined catalyst may be a potential candidates for practical use in the future.

Key words: Lean-burn automobile exhaust, Noble metal catalyst, NO reduction, Selective catalytic reduction, Synergistic effect

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