Synthesis and characterization of carbon nanotubes

Catalytic synthesis and physicochemical characterization of multi- and single-wall carbon nanotubes are presented. Supported transition metal(s) catalysts were prepared by different methods and were tested in the production of nanotubes by decomposition of hydrocarbons at 700 and at 1000 °C, using a fixed bed flow reactor. The carbon deposits were measured and the quality of the nanotubes was characterized by transmission electron microscopy. The inner and outer diameters of the nanotubes were also measured and the diameters distribution histograms were established : Thick multi-wall straight and coiled nanotubes with inner diameters (minimum-[average]-maximum) of 4-[6]-10 nm, outer diameters of 8-[25]-50 nm and with lengths up to 50 mm. Thin multi-wall straight and coiled nanotubes with inner diameters of 3-[4]-7 nm, outer diameters of 5-[15]-25 nm and with lengths up to 50 mm. Very thin multi-wall straight and coiled nanotubes with inner diameters of 2-[4]-7 nm, outer diameters of 3-[10]-15 nm and with lengths up to 50 mm. Single-wall nanotubes isolated or as bundles with diameters of 1-[2]-4 nm and with lengths up to 1 mm. The influence of various parameters such as the way of catalyst preparation, the nature and the pore size of the support, the nature of the metal(s), the quantity of catalyst active particles and the reaction conditions on the nanotubes formation were studied.