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炭二氧化硅复合气凝胶的合成及结构分析

陈 亮, 张 睿, 龙东辉, 凌立成   

  1. 华东理工大学 化学工程联合国家重点实验室, 上海 200237
  • 收稿日期:2008-10-07 修回日期:2008-12-11 出版日期:2009-07-20 网络出版日期:2009-07-20

Synthesis and Structure of Carbon/Silica Hybrid Aerogels

CHEN Liang, ZHANG Rui, LONG Dong-Hui, LING Li-Cheng   

  1. State Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai 200237, China
  • Received:2008-10-07 Revised:2008-12-11 Published:2009-07-20 Online:2009-07-20

摘要:

将二氧化硅溶胶和间苯二酚-甲醛溶液混合,经溶胶凝胶反应得到复合湿凝胶. 再经超临界干燥和炭化得到炭-二氧化硅复合气凝胶. 分别用氢氟酸刻蚀和空气烧蚀复合气凝胶中的二氧化硅和炭,得到结构完整的炭气凝胶和二氧化硅气凝胶. 复合湿凝胶经常压干燥、炭化和氢氟酸刻蚀能得到炭干凝胶. 利用透射电镜和低温氮气吸附对上述凝胶的微结构进行了表征. 结果表明:复合气凝胶中,炭和二氧化硅纳米网络各自连续并相互嵌套. 由于二氧化硅纳米网络的支撑作用,复合凝胶在超临界干燥和高温炭化过程中体积收缩减小,网络塌陷降低. 所得炭气凝胶具有高比表面(934m2/g)和高孔容(3.9cm3/g)的特点.

关键词: 气凝胶, 复合, 孔结构

Abstract:

Hybrid hydrogels were synthesized by sol-gel polymerization of resorcinol and formaldehyde added by colloidal silica solutions. Carbon/silica hybrid aerogels were prepared from the hydrogels by supercritical drying and carbonization. Carbon aerogels and silica aerogels were obtained by removing silica with HF etching and carbon with air burning from the hybrid aerogels respectively. Carbon xerogels were prepared by ambient drying, carbonization and HF etching from the hydrogels. The microstructures of the four kinds of gels were characterized by TEM and N2 adsorption. It is found that the carbon and silica frameworks are continuous and interpenetrated each other. The silica framework can improve the strength of hybrid gels, which can decrease the volume shrinkages by preventing collapse of the hybrid framework during supercritical drying and carbonization, resulting in carbon aerogels with high specific surface area of 934m2/g and large total pore volume of 3.9cm3/g.

Key words: aerogel, hybrid, pore microstructure

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