Sol-gel formation of reticular methyl-silicate materials by hydrogen peroxide decomposition

A new method for the formation of reticular silicate and organically modifi ed silicate is introduced. Monoliths were prepared by incorporating a few p ercent hydrogen peroxide in the sol-gel starting solution. For example, inc orporation of 6-10 % (v) hydrogen peroxide in base catalyzed sol-gel precur sors of methyl-Ormosil yielded macroporous monoliths with a bi-modal pore s ize distribution. The average characteristic pore diameters were approximat ely 1.2 nm and 0.7 mu m, depending on the sol-gel precursors used and the p reparation protocol. The specific surface area was approximately 160 m(2)/g , contributed mainly by the microporous structure. A similar preparation pr ocedure without hydrogen peroxide yielded only fractured or powdery materia ls. Presumably, the decomposition of the hydrogen peroxide yielded microbub bles, which formed templates for the polycondensation reaction. SEM, nitrog en adsorption isotherms and small angle X-ray spectroscopy were used to cha racterize the reticular materials.