Preparation Studies Titania Nanotube Arrays With

is an important semiconductor material with special abilities to photoelectric conversion and photocatalysis. The structure and morphology have significant effects on its two properties. In this thesis, this studying is focused on the fabrication, modification, and thermal treatment of highly ordered, vertically oriented TiO2nanotube arrays and its photocatalytic properties.1. The highly ordered, vertically oriented TiO2nanotube arrays:fabrication, thermal treatment and characterization.The highly ordered, vertically oriented TiO2nanotube arrays were synthesized by anodic oxidation of titanium foils in fluoride-based electrolytes under different experimental conditions such as temperature and voltage. The fluoride-based electrolytes included ethylene glycol, distilled water, ammonium fluoride and tungsten acid. The results of SEM showed that temperature had great effect on the pore size and wall thickness. The lower temperature had the smaller pore size and wall thickness. The pore size of the TiO2nanotube arrays prepared at50℃was about89-102nm, and the wall thickness is about23-28nm. And the pore size of the TiO2nanotube arrays prepared at30℃was about88-94nm, and the wall thickness was about18-20nm. The samples were heat treated at heating rate5℃/min at the temperature500℃,700℃and900℃. XRD data showed that its structure is anatase at500℃,700℃with the increasing of temperature to900℃, the part of anatase transformed to rutile. SEM results showed that the nanotube arrays formed granular titanium oxide.2. The modification, heat treatment and characterization results of TiO2nanotube arrays.In this thesis, the cobalt-doped, manganese-doped and cobalt/manganese co-doped TiO2nanotube arrays were successfully made by heat treatment. The results from the SEM micrographs indicated that there were many particles on the surface of the nanotube arrays. The results of XRD suggested that the excessive doped cations formed itself metal oxiedes.3. The experimental results of photocatalytic degradation of organic pollutants showed that the degradation efficiency depended on the experimental conditions such as the temperature of the electrolyte, electrolytic voltage, cations doped and thermal treatment temperature.1) Under the same conditions of thermal treatment temperature, electrolyte temperature had a significant effect on degradation efficiency, the curves of absorbance-time showed that the photocatalytic efficency of the samples prepared at30℃was better than that of at50℃.2) The electrolytic voltage and thermal treatment temperature also had a significant effect on degradation efficiency. The photocatalytic efficency of the samples prepared at40V was better than that of at50V and30V. The degradability of the samples calcined at different temperatures were η700=1.41205>η500=1.02209>η900=0.68952, it indicated that the degradability decreases with increasing temperatures.3) Cations doping also had great effect on degradation efficiency:The sequence of degradability was ηd=1.45906> ηc=1.44585> ηb=1.42774> ηa=1.41205(ηa representing the degradability of pure TiO2nanotube arrays, ηb representing the degradability of Co-doped TiO2nanotube arrays, ηc representing the degradability of Mn-doped TiO2nanotube arrays, ηd representing the degradability of cobalt/manganese co-doped TiO2nanotube arrays). The results showed that the cobalt/manganese co-doped TiO2nanotube arrays had good photocatalytic efficeccy.