Plasma-Assisted Conversion of Ethanol into Carbon Nanostructures

Abstract

Conversion of liquids into some kind of materials has always been highly interesting, and the best case might be the general case for carbon since it is an abundant element. There are many forms of carbon nanostructures such as carbon nanotubes (CNTs), graphene, carbon black, nanodiamonds, fullerene, and many more. These carbon allotropes have some special properties that make them of interest, but graphene and carbon nanotubes are the most motivating. Synthesis paths of all said nanostructures have recently been explored in liquids with plasma assistance. This pathway, which could improve processes, suppress precursors in liquids, including impurities, makes processes easier, faster, cheaper, or more environmentally friendly. According to some recently published studies, nanocarbon synthesis in ethanol is mostly produced by in-liquid plasmas called sparks, arcs, etc. Unlike other researchers, we decided to use the simple model setup, with an atmospheric pressure plasma jet, where plasma forms in the gas phase over a liquid surface and interacts with liquid. The experiments have been done in ethanol or ethanol mixture with water, and obtained results have indicated an interesting fast pathway to convert ethanol into nanocarbons. With this process, the micro and nanostructures were produced in a matter of minutes by the degradation and conversion of ethanol. The produced structures were at first mostly amorphous carbons. However, with a graphite sheet submerged in the ethanol, the size of produced structures reduced, and structured carbon was synthesized. Furthermore, with the optimization of plasma parameters, the pathways of conversions could be tailored, forming other forms or desired carbons, especially graphene.