Investigating the Graphitization Mechanism of SiO2 Nanoparticles in Chemical Vapor Deposition

The use of SiO2 as a catalyst for graphitic nanostructures, such as carbon nanotubes and graphene, is a new and rapidly developing catalyst system. A key question is whether carbide phases form in the reaction. We show the formation of SiC from SiO2 nanoparticles for the synthesis of graphitic carbon nanostructures via chemical vapor deposition (CVD) at 900 degrees C. Our findings point to the carbothermal reduction of SiO2 in the CVD reaction. The inclusion of triethyl borate apparently accelerates the process and leads to improved yields. The study helps better understand the growth mechanisms at play in carbon nanotube and carbon nanofiber formation when using SiO2 catalysts.