The Study Of The Preparation And Property Of CNTs And TiO₂ Nanotube Arrays

Herein this thesis reports the influence of catalyst calcination on carbon nanotubes growth over Co/Mo/Mg. Samples were analyzed by using XRD, SEM, Raman and TGA, the yield and morphology of carbon nanotubes was found to depend on the change of oxidation states of Co in the catalyts by calcination. The growth of single-walled carbon nanotubes could be attributed to the existence of Co3O4, and the growth of multi-walled carbon nanotubes was attributed to Mg(Co)MoO4. While the CoO obtained after calcination above 900℃was inactive for carbon nanotubes growth.The TiO2 nanotubes array was prepared by constant voltage anodic oxidation on the surface of pure titanium as a new catalysts carrier, impregnated NiO and MnOx respectively for the CVD and SCR research. The CNT grew successfully out of the TiO2 nanotubes. Catalytic reduction of NOx with NH3 was studied over MnOx coated TiO2 nanotube arrays prepared by anodic oxidation. When the MnOx were deposited inside the TiO2 nanotubes, a good NOx removal efficiency was achieved under relatively low reaction temperature, such that a NOx removal efficiency of over 90% was always obtained at temperature between 150℃and 250℃, particularly at 200℃, the NOx removal efficiency reached 99.9%. However, when the reaction temperature was higher than 250℃, a suppression of NOx removal was observed, probably because the diffusion of NO molecules into TiO2 nanotubes was controlled by Knudson diffusion.