High selectivity in double-walled carbon nanotube purification by high temperature oxygen/chlorine gas treatment.

摘要

Carbon nanotube (CNT) synthesis methods have been largely improved, making possible mass production. Nevertheless, as-prepared CNTs are usually produced together with metallic and carbonaceous impurities. However, these impurities may have a direct influence on the properties of carbon nanotubes samples. Thus, purification is a fundamental issue to be addressed. It is especially difficult to selectively remove both metallic and carbonaceous impurities without damaging or destroying the CNTs. The purification of CNTs by high temperature chlorine gas treatment was shown to be effective for removing metallic impurities [1]. The structural quality of the purified CNTs could also be preserved [2]. The effectiveness of this method allowed the development of a gas-phase purification treatment combining the use of oxygen added to chlorine subsequent to the use of pure chlorine [3]. We report here on elimination of both metal and carbon impurities from a double-walled carbon nanotubes (DWCNT) sample.