Templated direct growth of ultra-thin double-walled carbon nanotubes

TL;DR

This paper presents a universal method for synthesizing ultra-thin double-walled carbon nanotubes by stabilizing single-walled nanotubes at high temperature in vacuum, eliminating the need for precursors and improving yield and quality.

Contribution

The authors introduce a novel, universal approach to produce high-quality ultra-thin DWCNTs without precursors, applicable to various SWCNT types including metallic ones.

Findings

High-quality DWCNTs achieved with this method

Yield comparable or higher than traditional precursor methods

Applicable to different SWCNT types, including metallic ones

Abstract

Double-walled carbon nanotubes (DWCNTs) combined the advantages of multi-walled (MW-) and single-walled (SW-) CNTs can be obtained by transforming the precursors (e.g. fullerene, ferrocene) into thin inner CNTs inside SWCNTs as templates. However, this method is limited since the DWCNT yield is strongly influenced by the filling efficiency (depending on the type of the filled molecules), opening and cutting the SWCNTs, and the diameter of the host SWCNTs. Therefore, it cannot be applied to all types of SWCNT templates. Here we show a universal route to synthesize ultra-thin DWCNTs via making SWCNTs stable at high temperature in vacuum. This method applies to different types of SWCNTs including metallicity-sorted ones without using any precursors since the carbon sources were from the reconstructed SWCNTs and the residue carbons. The resulting DWCNTs are with high quality and the yield of inner tubes is comparable to/higher than that of the DWCNTs made from the transformation of ferrocene/fullerene peapods.