CARBON NANOTUBES PREPARED BY CATALYTIC DECOMPOSITION OF BENZENE OVER SILICA-SUPPORTED COBALT CATALYSTS

Carbon nanostructures were prepared by catalytic decomposition of benz ene on Co/SiO2 catalysts at 873 K. As a function of particle size and reactive mixture, carbon filaments and nanotubes were obtained and var ious shapes observed such as straight, curved and helically-coiled nan otubes. Particularly, it was shown that the helically-coiled nanotubes do not present an ordered atomic structure as it was predicted theore tically. However, the active catalytic particle as well as the reactiv e environment may play an important role in the growth of such nanostr uctures.