Energetics of the oxidation and opening of a carbon nanotube

TL;DR

This study uses first principles calculations to analyze how oxidation causes single-wall carbon nanotubes to open, revealing the energetics and stability factors involved in the process.

Contribution

It provides new insights into the energetics of nanotube opening by oxidation, including the stabilization of edges and the conditions for exothermic sublimation.

Findings

Oxygen rims stabilize open nanotube edges

CO2 sublimation becomes exothermic with increasing radius

Opening at the wall is less energetically favorable than at the cap

Abstract

We apply first principles calculations to study the opening of single-wall carbon nanotubes (SWNT's) by oxidation. We show that an oxygen rim can stabilize the edge of the open tube. The sublimation of CO$_2$ molecules from the rim with the subsequent closing of the tube changes from endothermic to exothermic as the tube radius increases, within the range of experimental feasible radii. We also obtain the energies for opening the tube at the cap and at the wall, the latter being significantly less favorable.