催化学报

催化学报 ›› 2006, Vol. 27 ›› Issue (4): 329-334.

• 研究论文 • 上一篇    下一篇

CeO2-TiO2催化剂的表面结构及其湿式氧化活性

杨少霞,祝万鹏,陈正雄,王建兵,周云瑞   

  1. 清华大学环境科学与工程系, 北京 100084
  • 收稿日期:2006-04-25 出版日期:2006-04-25 发布日期:1984-12-26

Surface Properties of CeO2-TiO2 Catalyst and Its Catalytic Activity in Wet Air Oxidation

YANG Shaoxia*, ZHU Wanpeng, CHEN Zhengxiong, WANG Jianbing, ZHOU Yunrui   

  1. Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China
  • Received:2006-04-25 Online:2006-04-25 Published:1984-12-26

PDF

757

被引次数

77

摘要： 采用溶胶-凝胶法和共沉淀法制备了CeO2-TiO2催化剂,利用N2吸附、X射线衍射、透射电镜、X射线光电子能谱和Zeta电位分析等手段表征了催化剂的表面结构性质. 以乙酸和苯酚为目标物,进行了湿式氧化高浓度乙酸和苯酚的活性测试,研究了CeO2-TiO2催化剂表面结构与活性之间的关系. 结果表明, Ce和Ti之间的相互作用使复合氧化物CeO2-TiO2催化剂具有小的晶粒尺寸和高的比表面积,催化剂表面化学吸附氧含量增加,且不同制备方法得到的CeO2-TiO2催化剂表面电位点不同,共沉淀法制备的催化剂更有利于乙酸和苯酚的吸附. 在湿式氧化反应中, CeO2-TiO2催化剂有较高的活性,其中共沉淀法制备的催化剂活性最高; 在230 ℃, 5 MPa条件下反应120 min后,乙酸COD去除率为79%; 在150 ℃, 4 MPa下反应120 min后,苯酚COD去除率为96%.

关键词: 湿式氧化, 氧化铈, 二氧化钛, 乙酸, 苯酚

Abstract: CeO2-TiO2 catalysts were prepared by sol-gel and coprecipitation methods. The physical properties including surface area, metal crystal phases, surface components, and pHPZC of the catalysts were characterized by N2 adsorption, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Zeta potentiometric analysis. The catalytic activity for wet air oxidation (WAO) of high concentration acetic acid and phenol was investigated. Moreover, the relationship between the surface structure and the catalytic activity was studied. The results showed that for the CeO2-TiO2 catalysts, the increase in the specific surface area and the decrease in the particle size are due to the interaction of Ce and Ti. A higher content of the chemisorbed oxygen was present on the surface of the CeO2-TiO2 catalysts. The pHPZC of the CeO2-TiO2-2 catalyst (pHPZC=4.6) prepared by coprecipitation was higher than that of the CeO2-TiO2-1 catalyst (pHPZC=3.2) prepared by the sol-gel method. The adsorption of acetic acid and phenol on the surface of CeO2-TiO2-2 is more effective. In WAO of acetic acid and phenol, the CeO2-TiO2 catalysts were very active. The activity of CeO2-TiO2-2 was the highest. By using the CeO2-TiO2-2 catalyst, about 79% COD removal was obtained in WAO of acetic acid at 230 ℃ and 5 MPa after 120 min reaction, while about 96% COD removal was achieved in WAO of phenol at 150 ℃ and 4 MPa after 120 min reaction.

Key words: wet air oxidation, ceria, titania, acetic acid, phenol