煤炭、石油和天然气的过度开采利用造成的能源短缺和环境污染问题，已成为各国关注的焦点问题；同时可持续发展是当今世界的重要主题之一，开发出无污染的环境自修复技术和可替代的清洁能源已成为当务之急。半导体光催化剂在环境和能源方面存在巨大应用潜能，引起了各国科研工作者的强烈研究兴趣。在众多半导体中，锐钛矿型TiO2具有生物和化学惰性、光生空穴的强氧化性、无毒性、价格低廉以及对光和化学腐蚀的长期稳定性等众多优点被认为是最有应用前景的催化剂。同时作为一种重要的半导体光催化剂，锐钛矿型TiO2由于在染料敏化太阳能电池、光催化剂、分解水、气体传感和离子监测等领域潜在的应用，受到研究者的青睐。然而，实际应用过程中要求进一步提高锐钛矿型TiO2的效率。为此，科研者对其开展了广泛深入的研究，譬如掺杂、半导体复合、表面修饰以及合成具有不同形貌的锐钛型TiO2颗粒等。研究发现，在光催化反应中，许多物理或化学过程是发生在TiO2表面的，如反应物分子的吸附、光激发电子到反应物分子的表面转移和产物分子的脱吸附等，这使得锐钛矿型TiO2的控制合成需要尽可能暴露出高活性晶面，以促进反应的进行，因此暴露出高活性晶面的锐钛矿型TiO2的可控合成成为研究的热点。锐钛矿型TiO2的{101}、{010}和{001}晶面所拥有的未饱和的五配位钛原子所占比例分别为50%，100%和100%，其平均表面能分别为0.44、0.53和0.90 J/m2。由于高表面能的晶面，具有较高的性能，因此合成具有高表面能的锐钛矿型TiO2对于提高其性能和扩大其应用是至关重要的。本论文以层状钛酸盐K2Ti4O9和Li2TiO3为钛源，通过质子交换、插层和剥离反应，得到剥离的纳米带或纳米片胶体悬浮液。调节溶液为设定的pH，然后分别采用常规水热法和微波辅助水热法成功制备了不同形貌和暴露晶面的锐钛矿型TiO2纳米晶。利用XRD、ICP、FE-SEM、TEM、HR-TEM、SAED、TG-DTA、氮气吸附脱附曲线等表征手段表征样品的结构、组成和形貌，对锐钛矿型TiO2的形成机制进行了阐述，并对其光催化和光伏性能进行了研究。主要研究内容和取得的成果如下：1. 以剥离的四钛酸纳米带胶体悬浮液为前驱体，采用常规水热法制备不同形貌、尺寸和特定暴露晶面的锐钛型TiO2纳米晶。以层状K2Ti4O9为原料，通过离子交换、四甲基铵根离子插层和剥离反应，获得含H2Ti4O9的纳米带胶体悬浮液。结果表明，通过改变溶液的pH和反应温度，可以获得不同形貌、晶型和暴露晶面的锐钛型TiO2纳米晶。当T ≥ 120 ºC，pH = 0.5时，产物是金红石型TiO2；当T ≥ 150 ºC，1.5 ≤ pH ≤ 4.0时，产物为暴露晶面与[111]晶带轴垂直的锐钛矿型TiO2纳米棒，即暴露晶面为[111]-晶面；当T ≥ 140 ºC，pH = 5.0时，产物为暴露晶面为[111]-晶面的立方体型和{010}晶面的菱形锐钛矿型TiO2纳米晶；当T ≥ 140 ºC，6.2 ≤ pH ≤ 13.0时，产物为暴露{010}晶面的梭型锐钛矿型TiO2纳米晶。并研究不同暴露晶面的TiO2的色素吸附性能及由其组装的染料敏化太阳能电池的光伏性能，结果表明暴露{010}晶面的锐钛矿型TiO2纳米晶展示了更优越的光伏性能。2. 以剥离的四钛酸纳米带胶体悬浮液为前驱体，采用微波辅助水热法制备不同形貌、尺寸和特定暴露晶面的锐钛型TiO2纳米晶。结果表明，当T ≥ 150 ºC，pH ≤ 1.0时，产物是金红石型、锐钛矿型和板钛矿型TiO2的混合相；当T ≥ 180 ºC，pH = 3.0时，产物为暴露晶面与[111]晶带轴垂直的锐钛矿型TiO2纳米棒；当T ≥ 160 ºC，pH = 5.0时，产物为暴露晶面为{010}晶面的长方块型和菱形锐钛矿型TiO2纳米晶；当T ≥ 160 ºC，7.0 ≤ pH ≤ 13.0时，产物为暴露{010}晶面的梭型锐钛矿型TiO2纳米晶。研究了暴露不同晶面且具有不同形貌的锐钛矿型TiO2拓扑转变机理及其色素吸附性能、光催化性能和光伏性能，并与商业化的P25 TiO2做对比。研究发现，光催化和光伏性能的增加顺序是表面无特定结晶面 < [111]-晶面 < {010}晶面。3. 偏钛酸锂的锂离子的抽出和剥离。以Li2CO3和锐钛矿型TiO2为原料，采用传统固相合成法合成了具有岩盐结构的层状Li2TiO3，研究了其锂离子的抽出和剥离性能。结果表明，偏钛酸H2TiO3经四甲基氢氧化铵插层、剥离后，获得了带孔的[TiO3]2–纳米片。4. 带孔纳米片的常规水热处理。以带孔的[TiO3]2–纳米片胶体悬浮液为前驱体，通过改变溶液的pH，反应温度，获得了不同形貌、晶型和暴露晶面的锐钛型TiO2纳米晶。研究结果表明：当T ≥ 80 ºC，pH = 0.5时，产物是金红石型TiO2；pH = 1.0时，产物为锐钛矿型和板钛矿型TiO2的混合相；pH = 1.5时，产物为暴露晶面与[111]晶带轴垂直的锐钛矿型TiO2纳米棒；pH = 3.5时，产物为{010}暴露晶面的短梭型锐钛矿型TiO2纳米晶；当T ≥ 110 ºC、5.5 ≤ pH ≤ 11.5时，产物为暴露{010}晶面的长梭型锐钛矿型TiO2纳米晶。研究了不同形貌和暴露晶面的锐钛矿型TiO2的光催化性能和光伏性能，并与商业化的P25 TiO2做对比。研究发现，暴露{010}晶面的样品表现了较高的光催化性能和光伏性能。

The energy shortage and environmental pollution problems caused by the over-exploitation of coal, fossil oil and natural gas, have become the focus of all countries in the world. The sustainable development has become one of the most important topics in today’s world, and it is an urgent task to develop pollution-free environment self-repairing technology and seek clean alternative energy sources. Semiconductor photocatalysts have attracted worldwide attention for their potential applications in the field of environment and energy. Among various semiconductors, anatase-type titanium dioxide has been considered as one of the most promising photocatalysts due to its biological and chemical inertness, the strong oxidizing power of its photogenerated holes, non-toxicity, low cost, long-term stability against photo and chemical corrosion, As an important photocatalyst, anatase-type titanium dioxide has attracted increasing attention because of its potential applications in dye-sensitized solar cells, photocatalysis, water splitting, gas sensing and ion detecting, and so on. However, for the practical application, the efficiency of anatase-type titanium dioxide photocatalysis need to be further improved. Therefore, extensive and profound studies have been carried out, such as doping, semiconductor coupling, surface modification and synthesis of anatase-type titanium dioxide particles with different morphology. Tailored synthesis of anatase-type TiO2 with exposed active crystal facets has become a hot spots in the field of titanium dioxide materials because many physical or chemical reactions are carried out on the surface of the photocatalyst in the process of photocatalytic reaction, such as the adsorption of reactant molecules, surface transfer between photoexcited electrons and reactant molecules, and desorption of product molecules, and so on. For anatase-type titanium dioxide, the {101}, {010}, and {001} factets with unsaturated five-coordinate titanium atoms are 50%, 100%, and 100%, respectively, and the surface energy is 0.90, 0.53, and 0.44 J/m2 for {001}, {100}/{010}, and {101} facets, respectively. Due to the crystal with high surface energy always with high performance, therefore, it is very important to synthesize anatase-type titanium dioxide with exposed reactive surfaces to improve its performance and expand its application. In this work, anatase-type titanium dioxide nanocrystals with different morphologies and exposed facets were synthesized from the exfoliation of the nanoribbons or nanosheets colloidal suspension by using hydrothermal process or microwave assistant hydrothermal process. Prior to the hydrothermal treatment, the colloidal suspension was adjusted to a desired pH value. The precursor nanoribbons or nanosheets were prepared from the exfoliation of protonated and, subsequently, intercalated/H+-ion-exchanged K2Ti4O9 or Li2TiO3. The structures, compositions, and morphologies of the obtained titanium dioxide were characterized by XRD, ICP, FE-SEM, TEM, HR-TEM, SAED, TG-DTA and nitrogen adsorption-desorption isotherms analysis. The formation mechanism of the anatase-type titanium dioxide and the photocatalytic and photovoltaic performances were also investigated. The main results obtained are as follows:1. Synthesis of anatase-type titanium dioxide with different morphologies, crystal size and specific crystal facet from tetratitanate nanoribbons colloidal suspension by using conventional hydrothermal process. The precursor nanoribbons were prepared from the exfoliation of the protonated and, subsequentely, tetramethylammonium/H+-ion-exchanged K2Ti4O9. The results show that anatase-type titanium dioxide with various morphologies, crystal form and exposed crystal facets can be obtained by adjusted the pH value of the reaction solution and the reaction time. The rutile-type titanium dioxide were formed at pH = 0.5 while temperatures high than120 ºC, whereas the [111]-faceted nanorod-shaped anatase-type titanium dioxide were preferentially formed at pH 1.5~4.0 while temperatures high than 150 ºC. The [111]-faceted cuboid and {010}-faceted rhombic anatase nanocrystals and the {010}-faceted spindle-shaped anatase nanocrystals were preferentially formed at pH = 5.0 and pH 6.2~13.0, respectively, while temperatures high than 140 ºC. The adsorption behavior and the dye-sensitized solar cell performances of the anatase nanocrystals with different exposed facets were also investigated, the results show that the {010} facet exhibits excellent photovoltaic performance.2. Synthesis of anatase-type titanium dioxide with different morphologies, cyrsyal size and specific crystal facet from tetratitanate nanoribbons colloidal suspension by using microwave assisted hydrothermal approach. The results show that the mixture of anatase, rutile and brookite were formed at pH ≤ 1.0 while temperatures high than150 ºC. The [111]-faceted nanorod-shaped anatase nanocrystals were preferentially formed at pH = 3.0 while temperatures high than180 ºC. The {010}-faceted anatase nanocrystals with morphologies of cuboid, rhombic, and spindle were preferentially formed at pH 5.0~13.0 while temperatures high than160 ºC. The topotactic transformation reaction mechanism, the adsorption behavior, the photocatalytic and photovoltaic performances of the anatase-type titanium dioxide with different morphologies and exposed facets were also investigated, and compared with the commercial P25 titanium dioxide. The photocatalytic activity and photovoltaic performance were enhanced in an order of surface without a specific facet < [111]-faceted surface < {010}-faceted surface.3. The delithation and exfoliation of lithium ions from well-crystallized Li2TiO3. The layered Li2TiO3 were synthesized via conventional solid-state calcinations by using the Li2CO3 and anatase-type titanium dioxide as the raw materials. The delithation and exfoliation of lithium ions were investigated. The [TiO3]2– nanosheets with cavity within the layer were obtained from the tetramethylammonium intercalation and exfoliation of the H2TiO3.4. Hydrothermal treatment the nanosheets with cavity within the layer. The anatase-type titanium dioxide with different morphologies, crystal size and specific crystal facet were synthesized from the [TiO3]2– nanosheets colloidal suspension by using conventional hydrothermal process. The results show that when temperatures higher than 80 ºC, the rutile-type titanium dioxide were formed at pH = 0.5, the mixture of anatase and rutile were formed at pH = 1.0, and the [111]-facted nanorod-shaped anatase nanocrystals were preferentially formed at pH = 1.5, whereas the {010}-faceted anatase nanocrystals with morphology of short spindle were preferentially formed at pH = 3.5. The long spindle anatase nanocrystals with exposed {010}-facets were preferentially formed at pH 5.5~11.5 while the temperatures higher than 110 ºC. The photocatalytic and photovoltaic performances of anatase nanocrystals with different morphologies and exposed facets were investigated, and compared with the commercial P25 titanium dioxide. The results show that the anatase nanocrystals with exposed {010} facet exhibit excellent activity properity and photovoltaic performance.