物理化学学报 >> 2002, Vol. 18 >> Issue (03): 193-196.doi: 10.3866/PKU.WHXB20020301

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Sn0.5Ti0.5O2催化剂上SO2、NO和CO反应的机理

刘赵穹;马骏;张昭良;杨锡尧   

  1. 北京大学化学与分子工程学院,北京 100871
  • 收稿日期:2001-11-27 修回日期:2001-12-29 发布日期:2002-03-15
  • 通讯作者: 杨锡尧 E-mail:yangxy@pku.edu.cn

The Mechanism of SO2, NO and CO Reaction over Sn0.5Ti0.5O2 Catalyst

Liu Zhao-Qiong;Ma Jun;Zhang Zhao-Liang;Yang Xi-Yao   

  1. College of Chemistry and Molecular Engineering, Peking University,Beijing 100871
  • Received:2001-11-27 Revised:2001-12-29 Published:2002-03-15
  • Contact: Yang Xi-Yao E-mail:yangxy@pku.edu.cn

摘要: Sn0.5Ti0.5O2催化剂对NO+CO反应活性不高, 350 ℃时NO的转化率只有50%,但反应气中含有SO2时, NO的转化率接近100%,说明SO2对Sn0.5Ti0.5O2催化剂上的NO+CO反应具有促进作用. XPS表征发现,SO2+CO、SO2+NO+CO反应后催化剂表面有微量硫存在,而反应前没有检测到硫的存在.结合反应性能测定、瞬变应答实验、XRD、TPD研究等,发现催化剂上的表面硫参与了NO的催化还原反应,是NO+CO反应更重要的活性中心.据此,提出了SO2+NO+CO反应的氧化还原反应机理.

关键词: 脱硫, 脱硝, Sn0.5Ti0.5O2, 催化剂, 金红石, 反应机理

Abstract: SO2 shows a significant promoting effect on the activity of Sn0.5Ti0.5O2 solid solution catalyst for NO reduction with CO at 350 ℃. The mechanism of the promotion was studied by transient techniques combined with reaction test, XRD, XPS and TPD methods. The XPS analysis proves the existence of surface sulfur species, which was formed during the COSO2 or COSO2NO reaction. It was suggested that the surface sulfur weakened the N-O bond and promoted its split hence promoted NO reduction. Therefore, surface S is one of the more importance active site for NO reduction in the SO2NOCO reaction. The mechanism of SO2 promoted NO reduction by CO was proposed.

Key words: DeSOx, DeNOx, Sn0.5Ti0.5O2, Catalyst, Rutile, Reaction mechanism