高等学校化学学报 ›› 2004, Vol. 25 ›› Issue (1): 136.

• 研究论文 • 上一篇    下一篇

富氧条件下Cu/Al2O3催化剂上C3H6选择性还原NO的研究

张长斌, 贺泓, 余运波, 张润铎   

  1. 中国科学院生态环境研究中心, 北京 100085
  • 收稿日期:2002-12-18 出版日期:2004-01-24 发布日期:2004-01-24
  • 通讯作者: 贺 泓(1965年出生),男,博士,研究员,博士生导师.主要从事环境催化研究.E-mail:honghe@mail.rcees.ac.cn E-mail:honghe@mail.rcees.ac.cn
  • 基金资助:

    中国科学院百人计划;国家自然科学基金(批准号:50148018);“八六三”计划项目(批准号:2001AA643040)资助

Research of Selective Catalystic Reduction of NO with Propene over Catalyst Cu/Al2O3 in Excess Oxygen

ZHANG Chang-Bin, HE Hong, YU Yun-Bo, ZHANG Run-Duo   

  1. Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
  • Received:2002-12-18 Online:2004-01-24 Published:2004-01-24

摘要: 以Cu/Al2O3为催化剂,对富氧条件下C3H6为还原剂选择性催化还原NO反应进行了研究.活性评价结果表明,与高活性的Ag/Al2O3催化剂相比,Cu/Al2O3催化剂选择性还原NO的活性较低,NO的最高转化率仅为40%.在所考察的温度范围(473~723K)内,红外谱图中不存在有机含氮化合物(R—ONO和R—NO2)的特征振动吸收峰.作为反应中间体—NCO的前驱体,有机含氮化合物在Cu/Al2O3催化剂表面难以生成是造成催化剂选择性还原NO活性低的直接原因.在Cu/Al2O3催化剂上,NO2吸附能够优先发生,并以NO3-物种的形式覆盖在大部分催化剂表面.动态原位红外光谱实验发现,这种NO3-表面物种与C3H6的反应性较差,使生成有机含氮化合物的关键反应难以发生,但此时的催化剂表面有利于C3H6和O2的完全氧化反应,这是导致Cu/Al2O3催化剂选择性较低的根本原因.

关键词: Cu/Al2O3, Ag/Al2O3, 氮氧化物(NOx), 选择性催化还原(SCR), 原位FTIR

Abstract: The selective catalytic reduction (SCR) of NO with propylene was investigated over Cu/Al2O3 catalyst by using fixed-bed reactor and in situ FTIR and compared with Ag/Al2O3 which has a relative high activity in C3H6-SCR of NO. The highest conversion of NO is only 40% at about 650 K, when the catalyst was exposed to a gas mixture of NO/C3H6/O2/N2=0.08%/0.171 4%/10%/balance with W/F=0.018 g·s/mL. Surface R—NO2 and R—ONO species, which were observed on Ag/Al2O3 catalyst as the precursor of —NCO species, can hardly be found on Cu/Al2O3 catalyst surface in FTIR spectra under the same condition. This results in the low activity of Cu/Al2O3 catalyst for NO reduction. Through dynamic FTIR experiment, it was found that NO3- species, which are dominant surface species over Cu/Al2O3 catalyst, have a low activity with C3H6, so that the reaction producing R—NO2 and R—ONO is very difficult to take place.

Key words: Cu/Al2O3, Ag/Al2O3, NOx, Selective catalytic reduction (SCR), In situ FTIR

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