Synthesis of high surface area silica gels using porous carbon matrices

Porous silica was prepared using the sol-gel synthesis with porous carbon m atrices as a pore-forming support. Tetraethoxysilane (TEOS) was hydrolyzed in an acid medium in the presence of a substoichiometric amount of water. V arious carbon materials were used, among them Sibunit and catalytic filamen tous carbon. Carbon matrices were impregnated with hydrolyzed TEOS and drie d, then carbon was removed by burning out in air at 873 K. The obtained por ous silica samples were studied by adsorption and electron microscopic meth ods. The specific surface area as high as 1267 m(2)/g and pore volume as hi gh as 5.7 cm(3)/g were determined for some silica samples. Thus deposited S iO2 was found to cover the carbon surface copying its surface. With CFC use d as carbon matrix, silica nanotubes were obtained. Thermostability of such silica is significantly greater as compared to silica gels reported earlie r.