Synthesis of nanocarbon by high-voltage breakdown of hydrocarbons

Abstract

The object of research is the mechanisms of synthesis of nanocarbon structures in the process of electric high-voltage breakdown of hydrocarbons. The problem to be solved is the purposeful synthesis of various types of nanocarbon with small losses of raw materials. Mechanisms of nanocarbon formation in the process of high-voltage electric breakdown of hydrocarbons have been established. It is shown that a high-voltage breakdown leads to a cascade of chemical transformations. As a result of transformations, lower gaseous hydrocarbons are formed due to the destruction of molecules and higher ones – as a result of polymerization, and as a result of dehydrocyclization and polymerization with the participation of metal catalysts – various carbon nanostructures. The possibility of targeted synthesis of fullerene-like structures, nanotubes with diameters from 10 to 50 nm, nanofibers, and films is demonstrated. Experimental studies have confirmed that the qualitative and quantitative composition of nanocarbon can be varied in a wide range. With an increase in the number of carbon atoms or the number of C–C bonds in the raw material molecules, other things being equal, the practical yield of solid nanocarbon increases. It was determined that the synthesis of structured nanocarbon from a mixture of hydrocarbon gases, formed as a result of high-voltage breakdown of liquid hydrocarbons, actively occurs on the nickel-chromium catalytic surface. An increase in the area of the catalytic deposition surface leads to an increase in the yield of nanocarbon. The study of the ability of the obtained nanocarbon samples to absorb electromagnetic radiation confirmed the potential of the method of high-voltage breakdown of hydrocarbons for the synthesis of materials that weaken electromagnetic radiation at a frequency of 25 to 38 GHz. The greatest weakening is observed for samples consisting mainly of carbon nanotubes and nickel nanoparticles