Preparation of Mesoporous α-SiC from RF/SiO ₂ composite aerogels

RF/SiO ₂ gels were synthesized in one pot by simply mixing of the monomers, and then dried to aerogels by supercritical CO ₂ fluid drying. Mesoporous silicon carbide (SiC) was formed from the RF/SiO ₂ composite aerogels after heat treatment (carbothermal reaction at 1 500 °C for 3 h under Ar and air calcination at 550 °C for 3 h) and purifying (acid-washing, filtering, drying). XRD, FTIR, NMR, SEM, TEM and nitrogen adsorption/desorption porosimetry were used to characterize the as-prepared mesoporous SiC. The results indicate that the resulting SiC was pure α-SiC, the average crystallite size was approximately 15 nm. The mesoporous SiC specimen possessed a BET surface area of 106 m ²•g ^-1 which approached to the specific surface area of porous SiC or SiC nanoparticles reported in other papers, a narrow pore size distribution, and a fairly uniform size and array. These mesoporous SiC could possibly be used as thermal insulators, catalysts, adsorbents or electrode materials.