Comparison of two methods of carbon nanotube synthesis: CVD and supercritical process (A review)

Abstract

A carbon nanotube (CNT) is a miniature cylindrical carbon structure that has hexagonal<br />graphite molecules attached at the edges. Nanotubes look like a powder or black soot, but they're<br />actually rolled-up sheets of graphene that form hollow strands with walls that are only one atom thick.<br />Carbon nanotube has been one of the most actively explored materials in recent year(s) due to its<br />unique properties and wide range of applications. Various methods have been adopted to produce CNT,<br />including laser ablation, arc discharge and CVD process. Chemical vapor deposition (CVD) is parent to a<br />family of processes whereby a solid material is deposited from a vapor by a chemical reaction occurring<br />on or in the vicinity of a normally heated substrate surface. The resulting solid material is in the form of<br />a thin film, powder, or single crystal. Among these methods, the chemical vapor deposition method is a<br />cheap and simple method. Supercritical fluids, particularly supercritical CO2, have been used in various<br />areas such as nanoparticle and CNT synthesis. In this paper the CNT synthesis methods based on<br />CVD and using supercritical fluids were studied.