Synthesis of High-Surface-Area SiC through a Modified Sol−Gel Route: Control of the Pore Structure

Abstract

High-surface-area SiC has unique mechanical and thermal properties for use as a catalyst and sorbent support. A modified sol−gel route was chosen to synthesize SiC, where the precursor (phenyltrimethoxysilane) was hydrolyzed in the presence of a solvent (methanol) in order to enhance reaction rates and control the pore structure of the SiC formed on firing. High surface areas in the range of 450−620 m2/g and pore volumes in the range of 0.37−0.45 cm3/g were obtained. Use of NaOH instead of NH4OH in the final stage of gel formation resulted in a higher proportion of pores bigger than 50 A in the pore structure. Similar changes in pore structure were observed when a surfactant (sodium dodecyl sulfate) was added along with methanol to enhance the contact between the precursor and water.