Porous silicon oxycarbide glasses from hybrid ambigels

Highly porous ambigels (aerogel-like materials dried at ambient pressure) have been employed for the synthesis of porous siliconoxycarbide (SiOC) glass. Ambigels were synthesized from methyltriethoxysilane (MTES), (bistriethoxysilyl)methane (BTEM) and 1,2(bistriethoxysilyl)ethane (BTEE) as the starting precursors which were later pyrolysed yielding porous SiOC glass. The synthesized ambigels possess very high surface area and pore volumes and a maximum surface area of 1131 m2/g with a pore volume of 1.29 cm3/g could be achieved for the gels derived from BTEE. After pyrolysing the ambigels in inert atmosphere, the porosity has been retained and a surface area as high as 430 m2/g could be attained. Solid state NMR studies have been employed to verify the retention of Si–C bond in the pyrolysed glass.

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► Ambigels as precursors for porous siliconoxycarbide (SiOC) glass.
► Ambigels from bridged silane precursors shows high surface area and pore volume.
► Pyrolysed glass retained a maximum surface area of 452 m2/g.
► The 29Si MAS studies confirmed the retention of Si–C bonds in the pyrolysed glass.
► The monolithicity could also be maintained for the pyrolysed glass.