高等学校化学学报 ›› 2019, Vol. 40 ›› Issue (10): 2170-2177.doi: 10.7503/cjcu20190226

• 物理化学 • 上一篇    下一篇

Cu掺杂对Pt/Ba/CuxMg1-xAl2O4催化剂高温稀燃 NOx消除性能的影响

尹萌欣,刘东升,赵东越,丁彤,田野,李新刚()   

  1. 天津化工协同创新中心, 天津市应用催化科学与工程重点实验室, 天津大学化工学院, 天津 300354
  • 收稿日期:2019-04-18 出版日期:2019-10-08 发布日期:2019-08-20
  • 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(No.21878213)

Effect of Copper Doping on Lean NOx Trap Performance of Pt/Ba/CuxMg1-xAl2O4 Catalysts at High Temperatures

YIN Mengxin,LIU Dongsheng,ZHAO Dongyue,DING Tong,TIAN Ye,LI Xingang()   

  1. Collaborative Innovation Center of Chemical Science and Engineering(Tianjin), Tianjin Key Laboratory of Applied Catalysis Science & Technology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China
  • Received:2019-04-18 Online:2019-10-08 Published:2019-08-20
  • Contact: LI Xingang E-mail:xingang_li@tju.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China.(No.21878213)

摘要:

制备了一系列不同Cu掺杂量的Pt/Ba/CuxMg1-xAl2O4(x=0, 0.1, 0.3)催化剂, 将其应用于高温NOx储存还原(NSR)反应, 并探究了Cu掺杂量对催化剂NOx消除性能的影响. 结果表明, 储存组分BaCO3在NSR过程中存在再分散现象. 高温时催化剂的NOx消除性能取决于其NOx储存量, 而不是NO氧化和NOx还原性能. 高温时催化剂的NOx储存量与其上硝酸盐的热稳定性密切相关, Pt/Ba/MgAl2O4上NOx主要以离子态硝酸盐形式存在, 而掺杂Cu后催化剂上的NOx又增加了单齿硝酸盐的存在形式, 单齿硝酸盐具有更高的热稳定性, 因此掺Cu催化剂具有更大的NOx储存量. 在450~500 ℃范围内, Cu的掺杂显著提高了Pt/Ba/MgAl2O4的NOx消除性能; Pt/Ba/Cu0.1Mg0.9Al2O4催化剂的性能最佳, 450 ℃时的NOx消除效率高达90%.

关键词: 高温, Cu掺杂量, Pt/Ba/CuxMg1-xAl2O4, 热稳定性, NOx储存还原

Abstract:

A series of Pt/Ba/CuxMg1-xAl2O4 catalysts with Cu doping was synthesized and used in high-temperature NOx storage reduction reaction. The results demonstrate that BaCO3, the NOx storage component, redisperses in the NOx storage reduction process. Moreover, the De-NOx activity of the catalysts at high temperatures was determined by the NOx storage capacity, rather than the NO oxidation and NOx reduction ability of the catalysts. The NOx storage capacity of the catalysts is directly linked to the thermal stability of nitrate species stored on the catalysts. NOx mainly exists in the form of ionic nitrate species on Pt/Ba/MgAl2O4, while NOx mainly co-exists as ionic nitrate and monodentate nitrate species on the Cu-doped catalysts. We discovered that monodentate nitrate species show higher thermal stability than ionic nitrate species. As a result, the Cu-doped catalysts exhibit the larger NOx storage capacity and hence the higher De-NOx activity. At the temperature range from 450 ℃ to 500 ℃, the addition of Cu greatly enhanced the NOx removal percentage of the catalysts. Among all the catalysts, Pt/Ba/Cu0.1Mg0.9Al2O4 has the highest De-NOx activity with NOx removal percentage about 90% at 450 ℃.

Key words: High temperature, Cu doping amount, Pt/Ba/CuxMg1-xAl2O4, Thermal stability, NOx storage reduction