物理化学学报 >> 2013, Vol. 29 >> Issue (11): 2437-2443.doi: 10.3866/PKU.WHXB201309052

催化和表面科学 上一篇    下一篇

还原剂对La0.7Sr0.3Co0.8Fe0.2O3钙钛矿催化剂NOx储存性能的影响

贤晖1,2, 马爱静1, 孟明1,3, 李新刚1,3   

  1. 1 天津大学化工学院, 天津市应用催化科学与工程实验室, 天津 300072;
    2 北洋国家精馏技术工程发展有限公司, 天津 300457;
    3 天津化学化工协同创新中心, 天津 300072
  • 收稿日期:2013-07-03 修回日期:2013-09-05 发布日期:2013-10-30
  • 通讯作者: 李新刚 E-mail:xingang_li@tju.edu.cn
  • 基金资助:

    国家自然科学基金(U1232118,);天津市自然科学基金(11JCYBJC03700);教育部新世纪优秀人才支持计划(NCET-10-0615)及天津大学绿色合成与转化教育部重点实验室开放基金资助项目

Influence of Reductants on the NOx Storage Performances of the La0.7Sr0.3Co0.8Fe0.2O3 Perovskite-Type Catalyst

XIAN Hui1,2, MA Ai-Jing1, MENG Ming1,3, LI Xin-Gang1,3   

  1. 1 Tianjin Key Laboratory of Applied Catalysis Science & Technology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072;
    2 Pei-Yang Distillation Engineering Limited Company, Tianjin 300457;
    3 The Synergistic Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072
  • Received:2013-07-03 Revised:2013-09-05 Published:2013-10-30
  • Contact: LI Xin-Gang E-mail:xingang_li@tju.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (U1162103), Natural Science Foundation of Tianjin, China (11JCYBJC03700), Program for New Century Excellent Talents in University of China (NCET-10-0615), and the Key Laboratory for Green Chemical Technology of Ministry of Education, Tianjin University.

摘要:

采用溶胶-凝胶法制备了La0.7Sr0.3Co0.8Fe0.2O3钙钛矿催化剂,考察了还原剂种类(CO,C3H6,H2)对催化剂在氮氧化物储存还原(NSR)循环前后的氮氧化物储存量(NSC)和NO-to-NO2转化率的影响.O2程序升温脱附(O2-TPD)实验结果表明,CO还原后的钙钛矿催化剂上形成了较多的氧空位,而氧空位则是一种有效的NOx储存活性中心.活性测试和傅里叶红外变换(FTIR)光谱表征结果显示:在NSR循环中,以CO为还原剂时催化剂显示了最佳的氮氧化物(NOx)储存效果.进一步的研究结果显示,当采用CO作为还原剂时,经过三次NSR循环后,催化剂中出现了Sr3Fe2O7新物相,而该物相可能具有比La0.7Sr0.3Co0.8Fe0.2O3钙钛矿更佳的NOx储存性能.综上所述,CO作为还原剂时可能使钙钛矿催化剂产生更多的氧空位以及更易于储存NOx的Sr3Fe2O7物相,这些原因使其NOx储存性能得到了大幅度改善.

关键词: 稀燃, 钙钛矿, 氮氧化物, 储存, 还原, 还原剂

Abstract:

A La0.7Sr0.3Co0.8Fe0.2O3 perovskite-type catalyst was synthesized by a sol-gel method. The influence of different reductants (CO, C3H6, and H2) on the NOx storage capacity and NO-to-NO2 conversion of the perovskite was evaluated before and after the NOx storage-reduction (NSR) tests. Our O2temperature programmed desorption findings showed that a large number of oxygen vacancies were generated in the COreduced perovskite. These oxygen vacancies are effective sites for NOx storage. The catalytic tests and Fourier transform infrared (FTIR) spectroscopy results showed that during the NSRtests of catalysts that used CO as the reductant, the catalysts demonstrated excellent NOx storage performance. Further investigations revealed the generation of a new Sr3Fe2O7 phase in the catalyst. This new phase may possess better NOx storage ability than the La0.7Sr0.3Co0.8Fe0.2O3 perovskite. In conclusion, the NOx storage ability of the catalyst was greatly improved after reduction by CO due to an increase in oxygen vacancies and the generation of a Sr3Fe2O7 phase during NSR cycling.

Key words: Lean-burn, Perovskite, NOx, Storage, Reduction, Reductant

MSC2000: 

  • O643