催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (6): 970-976.DOI: 10.1016/S1872-2067(11)60385-9

• 研究论文 • 上一篇    下一篇

K/CeO2催化剂上碳黑催化燃烧性能及稳定性

单文娟*, 杨利花, 马娜, 杨佳丽   

  1. 辽宁师范大学化学化工学院功能材料化学研究所, 辽宁大连 116029
  • 收稿日期:2012-01-15 修回日期:2012-03-01 出版日期:2012-05-30 发布日期:2012-05-30

Catalytic Activity and Stability of K/CeO2 Catalysts for Diesel Soot Oxidation

SHAN Wenjuan*, YANG Lihua, MA Na, YANG Jiali   

  1. Institute of Chemistry for Functionalized Materials, College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, Liaoning, China
  • Received:2012-01-15 Revised:2012-03-01 Online:2012-05-30 Published:2012-05-30

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摘要： 采用不同的钾盐前体制备了一系列 K/CeO2 催化剂, 利用热重和程序升温氧化 (TPO) 等技术考察了其催化性能及稳定性. 结果表明, K/CeO2 催化剂可使碳黑完全燃烧温度降低近 200 ºC. 钾盐前体对催化活性和稳定性具有较大影响, 由于硝酸钾熔点低, 金属在载体上的流动性强, 有利于催化剂与碳黑的有效接触, 因而表现了较高的活性, 三次 TPO 循环试验中催化活性稳定. 碳酸钾的熔点高且碱性较强, 使碳黑燃烧生成的 CO2 不可逆吸附在其表面, 导致反应活性低, TPO 循环实验表明其反应速率降低, 失活明显.

关键词: 碳黑氧化, 钾, 氧化铈, 程序升温氧化, 稳定性

Abstract: A series of CeO2 supported potassium nitrate and carbonate catalysts were prepared by an impregnation method. The catalytic activity and stability for soot oxidation were investigated by thermal gravimetric/differential thermal analysis and temperature-programmed oxidation cycle techniques. K/CeO2 substantially promotes the catalytic activity, which can be gauged by the lowering of the soot total removal temperature by more than 200 ºC compared with the uncatalyzed reaction. The influence of K precursor on the catalytic activity and stability was addressed. The effect is discussed in terms of the combined functions of K and CeO2, potassium mobility and basicity. For potassium-promoted ceria catalysts the potassium nitrate can preserve the high catalytic activity and good stability through several cycles. When K was present as K2CO3, the activity and stability of catalyst were lower than those of KNO3/CeO2. This behavior is attributed to the higher melting point and stronger basicity of K2CO3 which lead to irreversible adsorption of CO2 generated during soot combustion on the catalyst.

Key words: soot oxidation, potassium, ceria, temperature-programmed oxidation, stability