Synthesis of carbon nanotubes and carbon onions by CVD using a Ni/Y catalyst supported on copper

Bamboo-shaped carbon nanotubes and carbon onions have been synthesized, respectively, by CVD using a novel Ni/Y/Cu catalyst at different reduction and reaction temperature (500–700 °C). Characterization of the as-prepared catalyst and carbon nanoproducts are investigated by X-ray diffractometer (XRD), transmission electron microscopes (TEM) and X-ray energy dispersive spectrometer (EDS). The results show that yttria doped in nickel catalyst plays a key role in keeping the activity of the catalyst by resisting or postponing the interaction between copper and nickel. Along with the temperature increasing, the morphologies of the carbon products will be changed: carbon nanotubes at 500 °C, carbon onions at 600 and 700 °C. The growth mechanisms of CNTs and carbon onions are discussed in details.