SiC/C aerogels from biphenylene-bridged polysilsesquioxane/clay mineral nanocomposite aerogels

In this work, SiC/C aerogels with a high specific surface area (> 1000 m(2)*g(-1)) and high porosity (> 90%) synthesized through carbothermal reduction of biphenylene-bridged polysilsesquioxane (BP)/clay mineral nanocomposite aerogels. BP/clay mineral nanocomposite aerogels first prepared via sol-gel method followed by supercritical CO2 (ScCO2) drying process, then used to form SiC/C aerogels by intermolecular carbothermal reduction. The exfoliated BP/clay mineral nanocomposite aerogel caused the growth of several millimeters long SiC nanowires (NWs) with a diameter in the range of 30-90 nm on the surface of SiC/C monolith aerogel and worm-like SiC nanostructures in the interior of SiC/C aerogel. Digital microscope, XRD, FE-SEM, FT-IR, TEM, HRTEM, SAED, HAADF-STEM, EDS, BET, and mercury porosimetry techniques employed to fully characterize the obtained products. Al2O3-assisted vapor-solid (VS) mechanism proposed for the growth mechanism of SiC NWs on the surface of aerogels.