Hydrogenation and Hydro-Carbonation and Etching of Single-Walled Carbon Nanotubes

TL;DR

This study systematically investigates how hydrogen plasma interacts with single-walled carbon nanotubes, revealing reversible hydrogenation effects, structural changes, and etching processes that depend on temperature and nanotube size, with implications for various applications.

Contribution

It provides a comprehensive experimental analysis of hydrogenation, hydro-carbonation, and etching of SWNTs, highlighting size-dependent stability and reversible property changes.

Findings

Hydrogenation causes structural deformation and reduced conductance.

Reversible changes occur upon thermal annealing at 500°C.

High-temperature reactions lead to nanotube etching, especially in smaller tubes.

Abstract

We present a systematic experimental investigation of the reactions between hydrogen plasma and single-walled carbon nanotubes (SWNTs) at various temperatures. Microscopy, infrared (IR) and Raman spectroscopy and electrical transport measurements are carried out to investigate the properties of SWNTs after hydrogenation. Structural deformations, drastically reduced electrical conductance and increased semiconducting nature of SWNTs upon sidewall hydrogenation are observed. These changes are reversible upon thermal annealing at 500C via dehydrogenation. Harsh plasma or high temperature reactions lead to etching of nanotube likely via hydro-carbonation. Smaller SWNTs are markedly less stable against hydro-carbonation than larger tubes. The results are fundamental and may have implications to basic and practical applications including hydrogen storage, sensing, band-gap engineering for novel electronics and new methods of manipulation, functionalization and etching of nanotubes.