催化学报

催化学报 ›› 2008, Vol. 29 ›› Issue (3): 221-227.

• 研究论文 • 上一篇    下一篇

Cu/La/CeO2-Al2O3的制备及其对丙烯选择性还原NO的催化活性

郭锡坤,林树东   

  1. 汕头大学化学系, 广东汕头 515063
  • 收稿日期:2008-03-25 出版日期:2008-03-25 发布日期:2012-03-01

Preparation of Cu/La/CeO2-Al2O3 and Its Catalytic Activity for Selective Reduction of NO with Propylene

GUO Xikun*, LIN Shudong   

  1. Department of Chemistry, Shantou University, Shantou 515063, Guangdong, China
  • Received:2008-03-25 Online:2008-03-25 Published:2012-03-01

PDF

881

被引次数

23

摘要： 将Al(NO3)3-Ce(NO3)3混合溶液滴入到NH4HCO3-NH3·H2O混合溶液中,采用共沉淀法制备了CeO2-Al2O3复合载体. 采用等体积浸渍法分别浸渍助剂La和活性组分Cu, 制备了Cu/La/CeO2-Al2O3催化剂. 考察了催化剂在富氧条件下对丙烯选择性还原NO反应的催化活性,并借助扫描电镜、原子力显微镜、X射线衍射、比表面积测定、红外光谱、热重分析、X射线光电子能谱和程序升温还原等方法研究了催化剂活性与结构之间的关系. 结果表明, CeO2-Al2O3复合载体能显著增大催化剂的比表面积和孔径,增加表面Lewis酸酸量,改善催化剂的还原性能; 助剂La能进一步增大催化剂的比表面积和孔径,增加表面Brnsted酸酸量,显著提高催化剂的热稳定性; 催化剂的粒径较小,对丙烯选择性还原NO反应具有较高的催化活性,最高催化活性时的温度较低.

关键词: 铜, 镧, 二氧化铈, 氧化铝, 丙烯, 选择性还原, 一氧化氮

Abstract: The CeO2-Al2O3 composite support was prepared by the coprecipitation method with a mixed Al-(NO3)3-Ce(NO3)3 aqueous solution dropping into a mixed NH4HCO3-NH3·H2O aqueous solution. The Cu/La/CeO2-Al2O3 catalyst was prepared by impregnation of CeO2-Al2O3 with promoter La and active component Cu aqueous solution. The catalytic activity of the catalyst for the selective reduction of NO with propylene in excess oxygen was investigated. The relationship between the catalytic activity and the structure of the catalyst was also explored by means of scanning electron microscopy, atomic force microscopy,X-raydiffraction, surface area measurement, infrared spectroscopy, thermogravimetry,X-rayphotoelectron spectroscopy, and temperature-programmed reduction. The CeO2-Al2O3 could remarkably enlarge the catalyst surface area and pore size, increase the amount of Lewis acidity, and enhance the reducibility. The La promoter could further enlarge the catalyst surface area and pore size and increase the amount of Brnsted acidity and the thermal stability. Consequently, the catalyst exhibited higher activity for the selective reduction of NO with propylene in excess oxygen. The NO conversion decreased slightly even in the presence of water vapor.

Key words: copper, lanthanum, cerium dioxide, alumina, propylene, selective reduction, nitric oxide