Single-walled carbon nanotubes are tiny tubular structures with remarkable strength, electrical conductivity, and potential for next-generation technologies. However, the smallest versions of these tubes—just a fraction of a nanometer wide—are notoriously unstable and extremely difficult to produce.
A research team from Qingdao University of Science and Technology, Suzhou Lab, Peking University and collaborators has now succeeded in selectively growing one of the smallest stable carbon nanotubes, known as the (5, 4) nanotube, which measures only 0.61 nanometer in diameter. Their results were recently published in Science Bulletin .
To achieve this, the scientists designed special rhodium-based catalysts supported on oxide materials. They discovered that both the metal clusters and the support surface played key roles in guiding nanotube growth. Using a rhodium/magnesia catalyst, they reached an impressive 56.9% yield of the (5, 4) nanotube—far higher than normally possible.
“Our simulations suggest that these nanotubes grow in a unique perpendicular way on rhodium clusters, which makes it easier to form such tiny structures,” said Qianru Wu, lead author and a doctoral student at Qingdao University of Science and Technology.
The study also highlights why noble metals like rhodium are promising for nanotube synthesis: they can operate at lower temperatures, have low carbon solubility, and interact strongly with supporting materials, all of which help control the shape and size of the nanotubes.
“This work shows that noble-metal catalysts can be powerful tools for producing carbon nanotubes with very specific structures,” explained Professor Maoshuai He, a senior author of the study. “It not only helps us understand how these nanotubes grow but also paves the way for their future use in advanced devices and materials.”
The breakthrough brings researchers one step closer to harnessing ultrathin carbon nanotubes for applications in nanoelectronics, and other cutting-edge technologies.
Science Bulletin
Experimental study