Aug. 13, 2009 Carbon nanotubes — tiny, rolled-up tubes of
graphite — promise to add speed to electronic circuits and
strength to materials like carbon composites, used in airplanes
and racecars. A major problem, however, is that the metals used
to grow nanotubes react unfavorably with materials found in
circuits and composites. But now, researchers at MIT have for
the first time shown that nanotubes can grow without a metal
catalyst. The researchers demonstrate that zirconium oxide, the
same compound found in cubic zirconia "fake diamonds," can also
grow nanotubes, but without the unwanted side effects of metal.
The implications of ditching metals in the production of carbon
nanotubes are great. Historically, nanotubes have been grown
with elements such as iron, gold and cobalt. But these can be
toxic and cause problems in clean room environments. Moreover,
the use of metals in nanotube synthesis makes it difficult to
view the formation process using infrared spectroscopy, a
challenge that has kept researcher