Hydrogen-induced Unzipping of Single-Walled Carbon Nanotubes

TL;DR

This study uses ab initio calculations to show how atomic hydrogen can unzip single-walled carbon nanotubes by breaking C-C bonds when chemisorbed on their exterior, supporting recent experimental findings.

Contribution

It predicts for the first time that exterior chemisorbed hydrogen can unzipp nanotubes by breaking C-C bonds, providing electronic structure insights.

Findings

H chemisorption is stronger on the exterior than interior of nanotubes.

Two rows of H atoms can break C-C bonds and unzip the nanotube.

Interior H chemisorption does not cause bond breaking.

Abstract

The chemisorption of atomic hydrogen on the single-walled armchair carbon nanotube is studied with ab initio calculations. A single H atom is found to be chemisorbed on both the inside and outside wall of the nanotube. The binding energy of H adsorption at the exterior of the nanotube is much greater than that at the interior of the nanotube. For the first time, we predict that two rows of H atoms chemisorbed on selective sites exterior to the nanotube can break the nearest-neighbor C-C bond of the nanotube through the concerted formation of C-H bonds, leading to the unzipping of the nanotube wall. We provide insights into the underlying electronic structure responsible for the H-induced unzipping of the nanotube, lending strong support to the recent experimental observations for the coalescence of single-walled nanotubes in the presence of atomic hydrogen. Interestingly, H atoms chemisorbed inside the nanotube do not lead to the breaking of the C-C bonds.