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Toxic gas detectors nanotubes

Multiwall nanotube from SiC Multiwall nanotube from SiC

Nanotubes are one of the most interesting products of nanotechnology. They are fine tubes of various materials with a diameter of a few nanometres (billionths of a metre) and a length of up to several millimetres. Carbon nanotubes in particular are notable for several interesting properties and for being excellent chemical nanosensors.

 

Elettra's contribution
It has been shown at Elettra that even minute concentrations of toxic gases, such as nitrogen dioxide, sulphur dioxide, nitric oxide and ammonia, can drastically alter the electrical resistivity of carbon nanotubes.
Measurement of variations of electrical resistance of a nanotube placed between two electrical contacts can therefore reveal the presence of a toxic gas, with a sensitivity better than one part in a million.
Initial results suggest that within a few years it should be possible to construct and market the first carbon nanotube gas sensors.
If specific molecules are attached to their surfaces, nanotubes can serve as nanosensors capable of detecting biologically interesting molecules and molecular aggregates such as DNA, proteins and viruses.

 

Facility: SuperESCA Beamline

Bibliography:
The Role of Metal Contact in the Sensitivity of Single-Walled Carbon Nanotubes to NO2; R. Larciprete, L. Petaccia, S. Lizzit, A. Goldoni; Journal of Physical Chemistry. C,. 111, p. 12169, 2007.