Preparation, Modification And Performance Study Of One-dimensional Titanium Dioxide Nanomaterials

With the development and universal use of portable electronic products and electric automobiles, a kind of electrode featured with the properties of fast charging, lightness, safe and reliable is urgently required. As a cheap and stable inorganic semiconductor materials, titanium dioxide(TiO2) has been deeply applied in energy and environmental fields, such as lithium-ion batteries and photocatalysis. Among the four main phases of TiO2, anatase and rutile have excellent photocatalytic performance. Brookite was difficult to be synthesized and thus be rarely reported. TiO2(B) is a special type namely Bronze which owned abundant internal space in crystal structure and could be used as channels for Li ion.Therefore, Ti O2(B) has a certain advantage to be used as a quick charging and discharging lithium battery electrode materials. Elongated titanium dioxide nanotubes provide a long electronic transmission distance. At the same time, one dimensional structures tend to possess higher specific surface area and better effects for photocatalysis and intercalation/deintercalation behavior of Li-ion. In this paper, on the basis of preparation and characterization of elongated TiO2 fibers, several aspects of study have been done to improve the structure of one dimensional Ti O2 nanomaterials.1. Two different methods were adopted to prepared two different forms of carbon coating TiO2 nanotube: carbon coated single TiO2 nanotube(C/TiO2) and reduced graphene oxide(RGO) coated TiO2 nanotube(RGO/TiO2). C/TiO2 composites have an improved specific capacity(> 240 mAh/g) compared with Ti O2(B)(222 mAh/g). However, since the carbon layer plays a negative role in a Li-ion’s movement, its specific capacity decreases fast under a high rate of charge/discharge test. As the carbon layer thickening, a further decline of the specific capacity was observed. Whereas RGO/TiO2 composites presented a higher specific capacity(289 mAh/g) than TiO2(B) did. At a relative higher rate(5 C), RGO/TiO2 composites remained at a higher specific capacity(148 mAh/g), which was larger than TiO2(B)’s(96 mAh/g). Moreover, under the ratio of 15 C, RGO/TiO2 composites remains the specific capacity of 88 mAh/g. 2. Second hydrothermal approach was adopted to prepare TiO2 nanoneedles. the proportion of Ti O2 crystal phases could be adjusted by regulating the pH value of second hydrothermal system via adding inorganic acid. In addition, the aspect ratio of TiO2 nanoneedles can be controlled by tailoring the stirring rates. The length of prepared TiO2 nano needle was about 100 nm under the static state. However,, the length of TiO2 nano needles has a significant increase to 600 nm and 1.2 μm when the magnetic stirring rates at 500 rpm and 900 rpm. The photocatalytic performance tests showed that TiO2 nanoneedles prepared at pH=0.5 has better photocatalytic performance. Ti O2 nanoneedles(109.81 m2/g) prepared at 500 rpm showed better photocatalytic performance than the nanoneedles(26.67 m2/g) prepared in static state.