Synthesis and characterization of monolithic, high surface area SiO2/C and SiC/C composites

Abstract

In this study, the synthesis and characterization of high surface area carbon-supported silica and silicon carbide aerogels are presented. An activated carbon aerogel with surface area greater than 3000 m² g⁻¹ was used as a support for the sol–gel deposition of silica. The resulting silica-coated carbon aerogel retained a surface area greater than 2000 m² g⁻¹ and showed improved thermal stability in air. The carbon-supported silicon carbide aerogel was made by the carbothermal reduction of the silica-coated carbon aerogel under flowing Ar at 1500 °C. The resulting monolith maintained a surface area greater than 2000 m² g⁻¹ and was stable to temperatures approaching 600 °C, 100 °C higher than that of the pristine carbon aerogel.