Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (08): 2217-2223.doi: 10.3866/PKU.WHXB20100824

• CATALYSIS AND SURFACE STRUCTURE • Previous Articles     Next Articles

Small-Angle X-Ray Scattering Studies of Carboxyl Functionalized

WU Bao-Hu1,4, ZHANG Shu-Cui1,4, TANG Tao1,4, XU Yao1, LIU Yi2, WU Zhong-Hua3     

  1. 1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P. R. China;
    2. Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201800, P. R. China;
    3. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China;
    4. Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2010-02-10 Revised:2010-04-30 Published:2010-07-23
  • Contact: XU Yao E-mail:xuyao@sxicc.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10835008).

Abstract:

Carboxyl functionalized SBA-15 type mesoporous molecular sieves synthesized via co-condensation process were characterized by small-angle X-ray scattering (SAXS). Correlation function and chord length distribution theory were used to analyze the pore structure, interface, and periodic information. The pore structure parameters calculated from chord length distribution theory were compared with the Barrett-Joyner-Halenda (BJH) model cal-culation results, which are based on conventional nitrogen adsorption-desorption tests. The results showed that the samples preserved the structure order of their mesostructures since no significant degradation occurred with an increase in carboxyl group loading, except for the samples with a high carboxyl loading of 50% (molar fraction, versus inorganic silica source). There are no significant deviations in the porod curves of all of the samples. The carboxyl groups may become internally embedded within the framework walls of the mesostructure, as opposed to being externally linked to the pore channels via condensation on surface Si—OH sites. Individual pore size and pore wall thickness distribution data were obtained from the chord length distribution theory calculation without modeling. The pore wall thickness distribution data, which are inaccessible by other method, are very helpful for a further understanding of the mesostructure materials.

Key words: SBA-15, SAXS, Mesoporous, Correlation function, Chord length distribution

MSC2000: 

  • O648.11