Double-walled carbon nanotubes with small diameters synthesized by catalytic chemical vapor deposition of methane

摘要

Double-walled carbon nanotubes (DWNTs) with small diameters have been synthesized by catalytic chemical vapor deposition at 900 ℃ under a mixture of methane and hydrogen gas with a conditioning catalyst. The conditioning catalyst is obtained by sonication an ethanol solution containing Al2O3 powder and (NH4)6Mo7O24·4H2O. The mixture of Fe (NO3)3.9H2O and MgO powder is used as the catalyst of DWNTs growth. The results shows that the conditioning catalyst can improve the quality and the ratio of DWNTs in the products, and as-synthesized DWNTs have inner tube diameters of 0.62-0.88 nm and outer tube diameters of 1.21-1.33 nm.