A Selectivity Window for RF Plasma Synthesis of Few-Layer Graphene Nanoparticles

Abstract Graphene and other sp 2 -hybridized carbon nanostructures are highly sought for their large surface area, novel electrical and optical properties, and potential applications for energy conversion/storage. Atmospheric pressure plasmas offer a scalable route to carbon nanoparticle synthesis, but controlling the carbon allotrope formation is a major challenge because methane plasmas can lead to a large variety of non-graphitic nanostructures such as amorphous carbon nanospheres. Here we report on a gas flow-and-composition-based selectivity window for few-layer-graphene synthesis using an atmospheric pressure radiofrequency plasma reactor. Our key finding is that selecting for wrinkled few-layer graphene nanoparticle formation as opposed to other allotropes of carbon nanoparticles can be achieved by solely adjusting methane concentration and flowrate. This result establishes that atmospheric pressure plasmas can go beyond general carbon nanoparticle synthesis and enable selective control over allotrope formation.