Multiwall carbon nanotubes synthesized by RF-CCVD on novel CaO supported catalysts

Multiwall carbon nanotubes were synthesized on the FeCoCaO and FeMoCaO catalysts by RF-CCVD at 750 °C, 850 °C and 950 °C, using acetylene as the carbon source. Analytically, it was found that the nanotubes are well crystallized, with outside diameters ranging between 10 and 60 nm and a ratio of the outside to the inside diameters of 2 to 3. The nanotubes did not present amorphous carbon and their purity increased with the temperature of synthesis. A relatively large number of metallic nanoparticles of various dimensions and shapes encapsulated inside the nanotubes were observed by TEM in most of the nanotube samples.