Carbon Xerogel-supported Iron as a Catalyst in Combustion Synthesis of Carbon Fibrous Nanostructures

The catalytically assisted self-propagating high-temperature synthesis of carbon fibrous nanostructures, where the iron-doped colloidal carbon xerogel is proposed as a catalyst system, was examined. The carbon xerogel was prepared through carbonization of an iron doped organic xerogel at temperatures ranging from 600 to 1050 °C. The reaction between calcium carbide and hexachloroethane in the presence of sodium azide is exothermic enough to proceed at a high temperature, self-sustaining regime. The combustion reactions of those mixtures enriched with iron-doped carbon xerogels were conducted in a stainless steel reactor—calorimetric bomb under an initial pressure of 1 MPa of argon. Scanning electron microscopy analysis of the combustion products revealed low yield of various type of carbon fibers (presumably nanotubes), which grew via the tip-growth mechanism. The fibrous nanostructures were found in the vicinity of the spot of ignition, while in the outer and cooler area of the reactor, dusty products with soot-like morphology dominated. No significant correlation between the pyrolysis temperature of the carbon xerogel and the morphology of the obtained carbon fibrous nanostructures was observed.