Interface engineering for chirality-selective growth of single-walled carbon nanotubes

The synthesis of single-walled carbon nanotubes (SWNTs) from supported catalyst holds great potential for achieving high yields while simultaneously enabling control over the chirality distribution. During the chemical vapor deposition (CVD) process, both the catalyst-support interface and SWNT-catalyst interface are of great importance in regulating SWNT growth. In this work, a series of silica aerogel supported monometallic catalysts, including cobalt (Co) and ruthenium (Ru), are designed for CVD growth of SWNTs. We reveal that the catalyst-support interface can be engineered through techniques such as plasma treatment of silica surface or high temperature annealing. This modification facilitates subsequent activation of uniformly dispersed catalyst nanoparticles for growing SWNTs. Crucially, the composition of metal catalyst significantly influences the dynamic SWNT-catalyst interface, ultimately governing the chirality distribution of the synthesized SWNTs. At a reaction temperature of 600 °C, silica-supported Co catalyst predominantly yields (6, 5) SWNTs with larger chiral angles, while supported Ru catalyst produces SWNTs with a more uniform distribution of chiral angles. The striking differences can be attributed to the distinct carbon solubility of Co and Ru, which dictate the prevailing modes of SWNT nucleation and growth.