物理化学学报 >> 2003, Vol. 19 >> Issue (10): 902-906.doi: 10.3866/PKU.WHXB20031004

研究论文 上一篇    下一篇

Ni/Ce-Zr-Al-O催化剂的表面碱性和CO2+CH4重整性能

李春林;伏义路;卞国柱   

  1. 中国科学技术大学化学物理系,合肥 230026
  • 收稿日期:2003-03-24 修回日期:2003-05-21 发布日期:2003-10-15
  • 通讯作者: 伏义路 E-mail:fulin@ustc.edu.cn

Surface Basicity and Catalytic Performance on Ni/Ce-Zr-Al-O Catalyst for CO2+CH4 Reforming

Li Chun-Lin;Fu Yi-Lu;Bian Guo-Zhu   

  1. Department of Chemical Physics, University of Science and Technology of China, Hefei 230026
  • Received:2003-03-24 Revised:2003-05-21 Published:2003-10-15
  • Contact: Fu Yi-Lu E-mail:fulin@ustc.edu.cn

摘要: 用水热法制备了不同NiO含量的Ni/Ce-Zr-Al-O催化剂.用H2-TPD (程序升温脱附),DRIFTS(漫反射红外傅立叶变换光谱),CO2-TPD等方法考察了NiO的含量对催化剂表面碱性的影响,并和反应稳定性以及抗积碳性能相关联.H2-TPD结果表明,随NiO含量的增加,催化剂表面的Ni含量增加.DRIFT和CO2-TPD结果表明CO2的化学吸附主要是碳酸盐和碳酸氢盐形式.添加少量Ni能够使表面碱性位数量显著增加,碱强度减弱.Ni可能优先占据在催化剂表面较强的碱性位上,再增加Ni的含量则会使碱强度减弱,碱性位有所减少,降低CO2的吸附性能,从而减弱从CO2获得活动氧以消碳的能力.这种作用使NiO含量为7.0%(w)的样品活性随反应进行而减低,积碳量是NiO含量为4.0%(w)的样品的3.7倍.

关键词: 镍基催化剂, CO2+CH4重整, CO2程序升温脱附, 表面碱性, 积碳

Abstract: Ni/Ce-Zr-Al-O catalysts were prepared by hydrothermal synthesis method. The effect of NiO content on the basicity of catalyst was investigated by using H2-TPD (temperature programmed desorption), DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy), and CO2-TPD.The catalytic performance was tested and the amount of coke deposition was measured. The H2-TPD result shows that the amount of Ni on the catalyst surface increases with the NiO content. DRIFT and CO2-TPD results show that the bicarbonate and carbonate are the predominant species of the CO2 chemisorptions. The addition of few Ni can promote obviously CO2 chemisorptions and weaken the intensity of basicity. While Ni metal is preferable to reside on stronger basic site, the increase of NiO content can weaken the basicity, decrease the amount of basic site and weaken the CO2 adsorption performance. It weakens the performance of eliminating coke by mobile oxygen originated from CO2.So the catalytic activity of the sample with 7.0%(w) NiO decreases during reaction, the amount of coke deposition is much higher than that of the sample with 4.0%(w) NiO.

Key words: Ni catalyst, CO2+CH4 reforming, CO2-TPD, Surface basicity, Coke deposition