Diameter-selective purification of carbon nanotubes by microwave-assisted acid processing

Narrowly diameter-distributed single-walled carbon nanotubes (SWCNTs) were purely achieved by a facile technique combining microwave irradiation with mixed acid-assisted dispersion. Using this process, besides removal of conventional impurities, both small SWCNTs with highly chemical reactivity and the outer layers of large double-walled carbon nanotubes with more topological defects were preferentially eliminated, retaining only pure SWCNTs of which the diameter distribution was significantly narrowed. The chemical structure of resulting materials was carried by Raman spectroscopy, and electron microscopies. Results revealed that the technique employed is of great efficacy not only for purifying carbon nanotubes, but also especially for narrowing carbon nanotubes. The dual effects of purifying and diameter distribution narrowing make this method promising for achieving high purity single-walled CNTs of specific types. The purification mechanism of the present technique was discussed in detail.

The dual effects of purifying and diameter distribution narrowing make the microwave-assisted technique promising for sorting high purity single-walled CNTs out from as-prepared materials comprising both impurities and mixed carbon nanotubes of different types and diameters..Figure optionsDownload as PowerPoint slideHighlights
► A unique technique enables purification of single-walled carbon nanotubes (SWCNTs).
► Uniform SWCNTs were sorting out from mixtures of few-layed carbon nanotubes.
► Diameter distribution of SWCNTs has been substantially narrowed.
► Microwave-assisted acid processing has proven to be effective for such purification.
► Purification mechanism was deeply investigated.