Oxidation stability of confined linear carbon chains, carbon nanotubes, and graphene nanoribbons as 1D nanocarbons

TL;DR

This study systematically compares the oxidation stability of linear carbon chains, carbon nanotubes, and graphene nanoribbons confined inside each other, revealing unexpected thermal stability and the influence of host confinement.

Contribution

It provides the first systematic analysis of oxidation stability of 1D nanocarbons inside host structures, highlighting the role of confinement and host type.

Findings

Linear carbon chains are thermally stable up to 500°C inside CNTs.

Stability increases with longer chains and narrower host tubes.

Graphene nanoribbons are the most stable among the studied nanostructures.

Abstract

Three typical one-dimensional (1D)/quasi-1D nanocarbons, linear carbon chains, carbon nanotubes, and graphene nanoribbons have been proven to grow inside single-wall carbon nanotubes. This gives rise to three types of hybrid materials whose behaviour and properties compared among each other are far from understood. After proving successful the synthesis of these nanostructured materials in recently published work, we have now been able to study their oxidation stability systematically by using resonance Raman spectroscopy. Surprisingly, the linear carbon chains, which have been theoretically predicted to be very unstable, are actually thermally stable up to 500 {\deg}C assisted by the protection of the carbon nanotube hosts. Besides, longer linear carbon chains inside narrower CNTs are more stable than the shorter ones inside larger tubes, suggesting that the thermal stability not only depends on the length of linear carbon chains alone, but it is correlated with the confinement of the host tubes in a more complicated manner. In addition, graphene nanoribbons come overall in view as the most stable confined structures. On the other hand, peculiarities like the higher stability of the (6,5) CNT over its (6,4) counterpart allow this study to provide a solid platform for further studies on the application of these 1D nanocarbons (including true 1D linear carbon chains) at ambient conditions.