Selective formation of carbon nanotubes over Co-modified beta zeolite by CCVD

Multiwall carbon nanotubes containing carbon-zeolite composite materials have been obtained by ethylene catalytic chemical vapor deposition (CCVD) on Co-modified beta zeolite powder. High carbon selectivity to nanotubes was achieved. The combined physical characterisation through several techniques, such as TEM, HRTEM, SEM, XRD, N-2 adsorption-desorption, allows to determine the geometric characteristics of nanotubes and their dependence of catalyst and synthesis conditions. (C) 2004 Elsevier Ltd. All rights reserved.