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

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Supported catalysts are crucial for synthesizing single-walled carbon nanotubes (SWNTs) with controlled chirality.
• The catalyst-support and SWNT-catalyst interfaces significantly influence SWNT growth during chemical vapor deposition (CVD).

Purpose of the Study:

• To design and investigate silica aerogel supported monometallic catalysts (Cobalt and Ruthenium) for CVD growth of SWNTs.
• To understand how catalyst-support interface engineering and metal catalyst composition affect SWNT chirality.

Main Methods:

• Plasma treatment and high-temperature annealing were used to engineer the silica-support interface.
• Monometallic Cobalt (Co) and Ruthenium (Ru) catalysts supported on silica aerogels were synthesized.
• SWNTs were grown via CVD at 600 °C.

Main Results:

• Engineered catalyst-support interfaces enhanced catalyst nanoparticle dispersion and activation.
• Silica-supported Co catalysts predominantly produced (6, 5) SWNTs with larger chiral angles.
• Silica-supported Ru catalysts resulted in a more uniform distribution of SWNT chiral angles.

Conclusions:

• The dynamic SWNT-catalyst interface, governed by metal catalyst composition and carbon solubility, is key to controlling SWNT chirality.
• Cobalt and Ruthenium catalysts exhibit distinct carbon solubility, leading to different SWNT nucleation and growth modes.
• This study demonstrates a method for tuning SWNT chirality through catalyst design and interface engineering.