Synthesis of Multi-walled Carbon Nanotubes on Ni/SiO2

Multi-walled carbon nanotubes were synthesized by Chemical Vapor Deposition on supported Ni/SiO2 using carbon monoxide as carbon source. The effect of Ni loading and feed gas on carbon nanotubes was studied. The yield of carbon was very low when Ni loading was 5% and the yield increased with the increase of Ni loading from 5% to 35%. Then the yield decreased after Ni loading is over 35%. The carbon nanotubes were characterized by TEM, HRTEM and XRD. It was found that the morphology of carbon nanotubes became poor with the increase of Ni loading. The optimum reaction temperature is 600. from both aspects of carbon yield and morphology. Without hydrogen in the feed gas, the diameter of carbon nanotubes was in a narrow range of 10 similar to 20nm. After hydrogen was introduced to the system, the amount of carbon was enhanced but the morphology became worse.