Template-free synthesis of fully collapsed carbon nanotubes and graphene nanoribbons by chemical vapor deposition

Abstract

Fe2O3/Al2O3 catalyst was prepared by simply calcining the mixture of commercial Fe2O3 and Al2O3 powders at 1000°C. The obtained Fe2O3/Al2O3 catalyst shows high efficiency for the synthesis of fully collapsed carbon nanotubes and graphene nanoribbons through the catalytic decomposition of methane at 900°C. The yield of the fully collapsed carbon nanotubes and graphene nanoribbons was 19.5wt%. Field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and thermal gravimetric analysis were used to characterize the products. A tip-growth mechanism for the fully collapsed carbon nanotubes was suggested based on the SEM and TEM images of products produced at the initial stage. The break through of the catalyst particle from graphite layers resulted in the crack and then cut open of the fully collapsed carbon nanotubes, which further resulted in the formation of the graphene nanoribbons.