物理化学学报 >> 2010, Vol. 26 >> Issue (08): 2217-2223.doi: 10.3866/PKU.WHXB20100824

催化和表面结构 上一篇    下一篇

羧基官能化SBA-15型介孔分子筛的小角X射线散射研究

吴宝虎1,4, 张书翠1,4, 唐 涛1,4, 徐耀1, 柳 义2, 吴忠华3   

  1. 1. 中国科学院山西煤炭化学研究所, 煤转化国家重点实验室, 太原 030001;
    2. 中国科学院上海应用物理研究所, 上海光源, 上海 201800;
    3. 中国科学院高能物理所, 北京同步辐射实验室, 北京 100049;
    4. 中国科学院研究生院, 北京 100049
  • 收稿日期:2010-02-10 修回日期:2010-04-30 发布日期:2010-07-23
  • 通讯作者: 徐耀 E-mail:xuyao@sxicc.ac.cn
  • 基金资助:

     国家自然科学基金(10835008)资助项目

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).

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摘要：

使用小角X射线散射(SAXS)技术对共缩聚法制备的羧基官能化SBA-15介孔分子筛进行了表征, 利用相关函数理论和弦长分布理论获得了羧基化分子筛的孔结构、界面和周期性信息, 辅以常规的氮气吸附-脱附测试, 并将基于Barrett-Joyner-Halenda (BJH)模型计算的孔结构与弦长分布理论得到的结果进行比较. 结果表明: 除了羧基引入量高达50%(摩尔分数, 相对无机硅源)的样品外, 随着羧基引入量的增加所有羧基官能化SBA-15均能保持较高的有序结构且有序度变化不大. 所有样品的Porod曲线均无明显偏离, 羧基基团倾向于进入介孔的骨架结构而不仅仅是键合在表面的Si—OH上. 利用弦长分布法, 无需建立模型, 可以得到独立的孔壁厚度分布和孔径分布, 尤其是其它方法无法给出的孔壁厚度分布, 对于进一步认识有序介观结构材料有很大帮助.

关键词: SBA-15, SAXS, 介孔, 相关函数, 弦长分布

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