A Study Of Synthesis,Magnetic Properties And Photocatalytic Activity Of Titanium Dioxide Coated Carbon Nanotubes

Carbon nanotubes?CNTs? have been widely studied in materials area due to the quantum confined effect,excellent electrical conductivity,chemical stability and light absorption performance.Recently,Iron filled multiwalled carbon nanotubes?Fe@MWNTs?have attracted much attention because of their distinct magnetic properties compared to the bulk ferromagnetic material.In this thesis,Fe-filled multiwalled carbon nanotubes were fabricated by chemical vapor deposition?CVD?method on Si substrates.The Fe@MWNTs were analyzed by scanning electron microscope?SEM?,transmission electron microscopy?TEM?,X-ray diffraction?XRD?,Raman spectroscopy,vibrating sample magnetometer?VSM?.The main results are as follows:?1?SEM shows that the morphology of samples have tubular structure,carbon nanotubes vertically arranged to the substrate surface.?2?EDS analyses indicate the presence of iron and carbon.?3?TEM results show individual discontinued Fe filled inside MWNTs.?4?X-ray diffraction analyses indicate the presence of both bcc and fcc iron texture.?5?Raman spectrum analysis shows that the products are graphitization structure.?6?VSM results show a pronounced magnetic anisotropy with the easy magnetization direction perpendicular to the substrate plane and parallel to the axis of the aligned MWNTs.Carbon nanotube-anatase titanium dioxide?CNT-TiO₂?composite systems are currently being considered for many applications including their potential use to address environmental problems.In the thesis,titanium dioxide coated carbon nanotube composite materials were synthetized using Fe@MWNTs.The sample characterization of pure TiO₂,CNTs-TiO₂ and Fe@CNTs-TiO₂ were analyzed by XRD and Raman,their UV-Vis and photocatalytic decomposition performance were tested.The main results are as follows:?1?XRD and Raman analyses indicate the TiO₂ in our samples have anatase crystal structure,and the carbon nanotubes are graphite structure.?2?UV-Vis results show that the absorption ability of Fe@CNTs-TiO₂ in ultraviolet and visible area is the strongest,pure TiO₂ shows the weakest absorption.?3?The photocatalytic degradation rate of Fe@CNTs-TiO₂ is about three times larger than pure TiO₂,carbon nanotubes have played a role as photosensitizer.