Herringbone-type carbon nanofibers with a small diameter and large hollow core synthesized by the catalytic decomposition of methane

摘要

Herringbone-type carbon nanofibers (CNFs) are a special kind of CNF with angles between the graphene plane direction and the axis of CNFs in the range of 0-90 deg 1. Theoretical calculations indicate that this type of nanofiber may exhibit some excellent properties, such as enhanced field emission, caused by the open edge sites, Aharonov-Bohm magnetic effects and magnetoconductance 2, and localized states at the Fermi level may give rise to materials with novel electronic and magnetic properties 3. Moreover, they can be expected to be used as absorbent materials, catalyst supports, gas storage materials and composite fillers, due to their special structural characteristics 4. Herringbone-type CNFs with large diameter and a very small or completely hollow core have been synthesized through a catalytic chemical vapor deposition (CVD) method by several groups 5,6. Recently, Endo et al. synthesized the cup-stacked-type CNFs with average diameter of 100 nm and a completely hollow core by the floating catalyst method 4. However, herringbone-type CNFs with very small diameter and large hollow core have been rarely reported. In this letter, we report that herringbone-type CNFs with an average outer diameter of 18 nm and a large hollow core were synthesized by catalytic decomposition of methane with a floating catalyst method.