Preparation And Characterization Of Metal Oxides(CeO₂,Gd₂O₃,TiO₂,ZrO₂)/carbon-nanotube Composites

Carbon nanotubes have demonstrated a wealth of exceptional structure, mechanical and electronic properties.In recent years, the investigations on the synthesis and properties of CNTs nanocomposites are one of the research hot spots in CNTs science and research area.In the presented paper, different oxides were respectively combined with carbon nanotubes to form novel nano-composites,The obtained composites were characterized using X-ray powder diffraction (XRD),X-ray energy dispersion spectrum(EDS),Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM);Nano-sized hole had been made on the surface of carbon nanotubes by air oxidation.Main research contents as followed:1.The purified carbon nanotubes were prepared with acid-treatment in nitric acid solution. The results show that purified carbon nanotubes were clean, many catalysts and unformed carbon had been removed; meanwhile,chemical functional groups had been attached the surface of carbon nanotubes,which was in favor of preparing carbon nanotubes nano-composites;the purified carbon nanotubes had good solubility in solvent.2.Two different ceria nano-particles/multi-wall carbon nanotubes (CeO2/CNTs) had been prepared by solvent-thermal method.Sizes, morphology, and conformation of CeO2 nanoparticles with CNTs were investigated by X-ray diffraction (XRD), Scanning electron microscope (SEM) and High Resolution transmission electron microscopy (HRTEM).Results indicate that the sizes, morphology,and conformation of CeO2 nanoparticles with CNTs can be controlled via H2O quantity.Spherical ceria nanoparticles along CNTs necklace-like supper-stable nanocomposites with size about 100 nm were synthesized at 7% H2O,otherwise, ceria nanoparticles coating on MCNTs with size about 20 nm were founded without H2O.Finally,the influence of H2O in methanol to the size of ceria nano-particles was discussed. 3.Two different gadolinium oxides/multi-wall carbon nanotubes (Gd2O3/CNTs) had been prepared by solvent-thermal method.The gadolinium oxide layer with thin coating sheath about 3-8 nm can be acquired at pH=3,while gadolinium oxide nanparticles with different shapes are got at pH=10.The structure,morphology of nanocomposites was characterized by X-ray powder diffraction (XRD),X-ray energy dispersion spectrum(EDS),Scanning electron microscopy (SEM), Transmission electron microscopy(TEM)respectively.The structure of gadolinium oxide can be established body-centered cubic phase finally.4.Anatase and Rutile had been deposited on the defects of the carbon nanotubes,the result of X-ray powder diffraction indicated Titania was tetragonal structure,single crystal;tetragonal structure zirconia single crystal nano-particles had been prepared by solvent-thermal method.The result of transmission electron microscopy(TEM) showed the size of zirconia was 6nm, based on Scherrer formula,5.4nm.5.Nano-sized hole had been made by air-oxidation controlling calefactive velocity,keeping time.As high energy dangling bonds exist on the defects of carbon nanotubes,air oxide carbon nanotubes by layer, finally forming nano-sized hole.