Enhanced purification of carbon nanotubes by microwave and chlorine cleaning procedures

Amid all the fancy equipment found in a typical nanomaterials lab, one of the most useful may turn out to be the humble microwave oven.

A standard kitchen microwave proved effective as part of a two-step process invented at Rice and Swansea universities to clean carbon nanotubes.

Basic nanotubes are good for many things, like forming into microelectronic components or electrically conductive fibers and composites; for more sensitive uses like drug delivery and solar panels, they need to be as pristine as possible.

Nanotubes form from metal catalysts in the presence of heated gas, but residues of those catalysts (usually iron) sometimes remain stuck on and inside the tubes. The catalyst remnants can be difficult to remove by physical or chemical means because the same carbon-laden gas used to make the tubes lets carbon atoms form encapsulating layers around the remaining iron, reducing the ability to remove it during purification.

In the new process, treating the tubes in open air in a microwave burns off the amorphous carbon. The nanotubes can then be treated with high-temperature chlorine to eliminate almost all of the extraneous particles.

ACS Advances – Enhanced purification of carbon nanotubes by microwave and chlorine cleaning procedures