在线客服: 点击这里给我发消息  新用户使用步骤:会员注册→充值→重新登入→进入资源
标题:High specific surface area TEOS-based aerogels with large pore volume prepared at an ambient pressure
时间:2020-03-26 12:30:09
DOI:10.1016/j.apsusc.2007.06.063
作者:Pradip B. Sarawade;Jong-Kil Kim;Ho-Kun Kim
关键词:silica aerogels; surface modification; ambient pressure drying; BET surface area; PSD; SEM
出版源: 《Applied Surface Science》 ,254 (2) :574-579
摘要:The experimental results on the synthesis of tetraethoxysilane (TEOS)-based silica aerogel with high specific surface area and large pore volume, via ambient pressure drying (APD) route, are reported. The silica aerogels were prepared by the acid-base sol-gel polymerization of TEOS precursor followed by the drying of the alcogels at an ambient pressure. The solvent present in the alcogel (i.e. ethanol) was replaced by a non-polar solvent such as hexane prior to the surface modification step. In order to minimize the drying shrinkage, the surface of the gels was modified using trimethylchlorosilane (TMCS) before the APD. The FTIR spectra of the surface modified aerogels showed Si-CH_3 peaks at 2965 and 850 cm~(-1). The effect of the base catalyst (NH_4OH) addition to the sol, at different time intervals (T), on the physical and textural properties of the resulting aerogels has been investigated. It has been observed that the surface area and the cumulative pore volume of the aerogels enhanced considerably from 819 to 1108 m~2 g~(-1) and 2.65 to 4.7 cm~3 g~(-1), respectively with an increase in the T value from 6 to 48 h. Silica aerogels with very low bulk density (0.06 g cm~(-3)), extremely high specific surface area (1108 m~2 g~(-1)) and large cumulative pore volume (4.7 cm~3 g~(-1)) could be synthesized by drying the alcogels at the ambient pressure. The aerogels were mesoporous solids with the average pore size ranging from 12 to 17 nm. The results have been discussed by taking into consideration the hydrolysis and condensation reactions during the sol-gel polymerization of the TEOS precursor.
大小:1030 kb
下载: 点击下载
预览:

浏览器不支持嵌入PDF阅读,打开新页面在线阅读

目录:
  • High specific surface area TEOS-based aerogels with large pore volume prepared at an ambient pressure
    • Introduction
    • Experimental
      • Aerogel preparation by two step sol-gel process
      • Characterization methods
    • Results and discussion
      • Surface modification and hydrophobic properties of the TEOS-based aerogels
      • Physical properties of the TEOS-based aerogels
      • Textural properties of the TEOS-based aerogels
    • Conclusions
    • Acknowledgements
    • References

本页内容由网络收集而来,版权归原创者所有,如有侵权请及时联系