Graphene-Like Carbon Nanostructures From Combustion Synthesis

Combustion synthesis (CS) (self-propagating high-temperature synthesis [SHS]) is a well-known method of nanomaterials production. Among its advantages one may point out the remarkable number of materials possible to design. It starts from a mixture of a strong reducer and an oxidant and leads to a variety of materials (also metastable). The process is carried out under high pressure (up to 5 MPa) in a reaction chamber and on average after initiation by ohmic heating takes less than a few seconds. Being self-sustainable it is environmentally friendly and favorable from the energetic point of view. The results of exploratory research on the autothermal synthesis of few-layered graphite via a CS are presented. It has been shown before that different carbon-related precursors can be directly converted into novel nanocarbons using strong reducers and the CS approach. In the current work such research is extended toward direct thermic reduction of standard calcium carbonate into few-layered graphene (FLG). As the oxidizer one may use a variety of minerals: dolomite siderite and limestone. Moreover the following reactant systems have been tested: Si/PTFE/NaCl and Si/CFx in order to obtain graphene flakes and SiC nanowires. To better characterize the product, XRD analysis and Raman spectroscopy might be used. The SHS process mechanism (thermodynamics kinetics of wave propagation) and in situ diagnostics optimization and control are also discussed. Finally, the presented approach is currently under further investigation with preliminary results for the GO/Ti reagent system. It can be additionally extended by a qualitative fractal analysis of the obtained nanomaterials.