Nanotubes made without metal catalyst

Massachusetts Institute of Technology researchers say they have created carbon nanotubes without using a metal catalyst.

The scientists said their finding that oxides, as well as metals, can grow carbon nanotubes changes science’s understanding of nanotube growth.

Carbon nanotubes — tiny tubes of graphite — promise to add speed to electronic circuits and strength to materials such as carbon composites that are used in airplanes and race cars. But the MIT scientists said a major problem has been that metals used to grow nanotubes react unfavorably with materials found in circuits and composites.

Now the researchers say they have, for the first time, shown nanotubes can grow without a metal catalyst by demonstrating zirconium oxide — the same compound found in cubic zirconia diamonds — can also grow nanotubes, but without the unwanted side effects of metal.

I think this fundamentally changes the discussion about how we understand carbon nanotubes synthesis, Professor Brian Wardle, who led the study, said.

Wardle said some scientists might find the study controversial since no one has ever proven anything other than a metal can grow a nanotube.

People report new metals (as catalysts) every so often, he said. But now we have a whole new class of catalyst and new mechanism to understand and debate.

The findings appear in the early online edition of the Journal of the American Chemical Society.