Synthesis of monolithic mesoporous silicon carbide from resorcinol-formaldehyde/silica composites

Resorcinol-formaldehyde/silica composite (RF/SiO2) gels were synthesized in one pot using a facile process. RF/SiO2 aerogels were obtained after supercritical carbon dioxide fluid drying. Monolithic mesoporous silicon carbide (SiC aerogels) was prepared from RF/SiO2 aerogels after carbothermal reduction and calcination. The as-prepared SIC products exhibited monolithic mesoporous morphology and possessed a BET specific surface area of 251 m(2)/g and a pore volume of 0.965 cm(3)/g. X-ray diffraction (XRD) and transmission electron microscopy (TEM) demonstrated that the resulting SiC aerogels were composed of alpha-SiC nanocrystals. The bulk density and skeleton density of SiC products is 0.288 g/cm(3) and 3.12 g/cm(3), respectively. The porosity of SiC products is 90.8%. The SiC aerogels were stable up to temperatures near 650 degrees C. (c) 2013 Elsevier B.V. All rights reserved.