随着社会的高速发展，环境污染问题已成为威胁人类生存的主要问题。TiO2材料拥有优异的光电化学性能、良好的化学稳定性、环境友好且成本低廉，在降解环境污染物和太阳能光电转换等方面有着巨大的应用前景。TiO2材料的性能与其形貌、粒度和表面结构等密切相关。为改善TiO2材料实际使用活性与效率，合成不同形貌、结构的TiO2材料具有重要意义。本文采用水热合成方法，制备了多种不同形貌与结构的微纳米TiO2材料，分别为具有大比例高能面的TiO2单晶及分级TiO2微纳米材料，均具有良好的光催化性能；系统研究了各种因素对产物形貌、性质及光催化性能的影响，并分析了可能的机理。论文的主要内容如下： 1、通过水热反应，制备得到具有分级结构的花状TiO2三维微纳米材料。该材料具有良好的锐钛矿结构；形态均一，粒径5 µm以下，由许多从中心发出、呈辐射状的TiO2纳米片组成；这些花状TiO2纳米材料具有208 m2/g 的较大比表面积；通过调节反应条件得到了不同形貌的产物；对花状TiO2分级微纳米材料的光催化性能进行了评价。2、通过水热法，可控合成出具有外露{001}面的球状TiO2分级结构材料。这种材料结晶度高，均一性好，光催化活性较强；通过调节反应条件得到了不同形貌的产物；研究了多种因素对产物形貌和结构的影响，并讨论了它们可能的生长机理。3、实现了不同粒径和不同{001}面比例锐钛矿TiO2单晶的可控合成，对其进行了系统的物理化学性质分析。结果证实，晶粒粒径是对不同晶面进行活性评价的重要前提，粒径越小，获得的单晶光催化活性越高；当粒径接近时，{001}面比例越高，晶体的光催化活性越高。本文利用水热法进一步合成了具有高比例{110}面的锐钛矿TiO2单晶，研究了温度、HF、双氧水等因素对实验产物形貌的影响，讨论了可能的机理，并对其光催化性能进行了研究。

Environmental pollution is considered the most important threat to human being. Titanium dioxide (TiO2) materials have attracted a great deal of attention due to their numerous applications in various fields, such as photocatalysis, photovoltaic cells, self-cleaning devices, sensors, Li-ion battery materials. The photo-catalysis of TiO2 plays an important role in the treatment of environmental pollution for many years. It is found that the performance of TiO2-based devices depends to a large extent on its physical and chemical nature, which is related to its crystal structure, size, morphology, and surface structure. So the controlled synthesis of TiO2 materials with different morphology and structure is very important for improvement of their reactivity and efficacy in practical application. In this paper, three-dimension (3D) flower-like TiO2 micro-nanostructures and TiO2 single crystals with exposed high energy facets have been synthesized by a facile and economical route. The impacts of various experiment parameters on the morphology and photocatalytic activity of above materials have been investigated. In addition, A possible mechanism has been proposed for explanation the growth process of TiO2 crystals. The main contents of the thesis are listed as follows：1. The three-dimension flower-like TiO2 hierarchical micro-nanostructure has been successfully synthesized using a hydrothermal technique. The XRD result suggests that the flowerlike hierarchical structures are typical anatase TiO2. They have uniform morphology and particle size. The size of these structures is about 5 µm. These flower-like TiO2 nanostructures are composed of many thin nanosheets. The specific surface area of flower-like TiO2 hierarchical micro-nanostructure is 208 m2/g. The photocatalytic reactivity of the flower-like TiO2 hierarchical micro-nanostructure has been estimated. 2. Hierarchical TiO2 nanospheres with dominant {001} facets has been synthesized by a easy hydrothermal process. The obtained hierarchical TiO2 nanospheres have uniform size and remarkable fraction of {001} facets. The influence of the reaction temperature, amount of HF, and reaction time on the morphology and the exposed facets was systematically studied. The photocatalytic activities of the hierarchical TiO2 nanospheres were evaluated. Owing to the special hierarchical architecture and high percentage of exposed {001} facets, the TiO2 nanospheres exhibit much enhanced photocatalytic efficiency.3. We have synthesized a set of anatase TiO2 single crystals with different percentage of {001} facets in uniform size, as well as a set of anatase TiO2 single crystals with different size in same percentage of {001} facets. The properties and structures of anatase TiO2 crystals were characterized by SEM, XRD, Raman, BET physical adsorption, XPS and UV-vis absorption spectra. The photocatalytic reactivity of the anatase TiO2 crystals were estimated by degradation of MB dye under UV light irradiation. We find that the smaller the size, the higher the photocatalytic reactivity is, for the anatase TiO2 crystals with same percentage of {001} facets. The higher the percentage of {001} facets, the higher the photocatalytic reactivity is, for the TiO2 crystals with same size. The same size is the main prerequisite for comparison of photoreactivity of {001} and {101} facets of anatase TiO2 crystal. This work clearly highlights the importance and necessity for establishment a comparison investigation prerequisite, which will promote our in-depth fundamental understanding on the different photocatalytic performance between the {001} facets and {101} facets of anatase TiO2 crystals; And the TiO2 crystals with high percentage of exposed {110} facets were controlled synthesized using a hydrothermal technique. The impacts of different experiment conditions, such as temperate, HF, and H2O2 etc, on the morphology of anatase TiO2 crystals with {110} facets were investigated. And a possible mechanism has been proposed for explanation the growth process of TiO2 crystals. The photocatalytic activity of the TiO2 crystals with {110} facets was estimated.