Elaborating ordered silicon carbide nanorods by preceramic polymer nanocasting

摘要

Meso- and micro-porous silicon carbide (SiC) ceramics have been successfully synthesized via a nanocasting process. These materials exhibit very high specific surface areas (from 240 to 760 m(2) g(-1)) and present morphologies of highly ordered SiC nanorods. Liquid allylhydropolycarbosilane or poly-1,3,5-trisilacyclohexane (pTSCH) were used as starting pre-ceramic polymers and were casted in a meso-porous silica template (SBA-15) which has undergone densification treatment. After thermal conversion, silica hard templates were subsequently removed by an aqueous hydrofluoric acid treatment leading to SiC inverse replicas of the template. The prepared meso-porous SiC products were thoroughly analyzed using small and wide angle X-ray scattering, electronic microscopies and nitrogen physisorption experiments. From our observations, the preparation procedure preserves the nanoscale structure of the silica templates and leads to highly porous SiC materials with tunable morphologies and specific surface areas.