【作者】 张阳；

【导师】 只金芳；

【作者基本信息】 中国科学院研究生院（理化技术研究所） ， 物理化学， 2009， 博士

【摘要】 TiO₂由于其宽的禁带宽度以及良好的稳定性,在半导体光催化领域得到最为广泛的重视,在污水处理、空气净化、抗菌以及自清洁等领域都有广泛的应用。另一方面,纳米材料的性质同其本身的结构,形貌,尺寸等密切相关,因此,可控形态和组成的纳米结构材料的制备和性能研究是当前纳米材料领域发展的研究热点。由于钛盐的高反应活性,使得在低温常压下可控合成TiO₂面临极大的挑战。本论文利用一种稳定的水性过氧化钛配合物（PeroxoTitanium Complex,缩写为PTC）作为合成TiO₂纳米粒子的前驱体,探索了其在低温可控合成钛基功能化纳米材料中的作用,并研究了所得产物的结构和性能,并研究了其在不同领域的应用,主要开展了以下几方面的工作:1、利用PTC结构随着体系pH值的变化而发生变化的特性,通过在常温常压下调节PTC前驱体的pH值,可控合成了不同晶型以及不同形貌的纳米TiO₂,在反应过程中,前驱体的pH值以及不同H₂O₂/Ti比值对产物晶型的影响很大,低的pH值（pH⁰）以及高的H2O₂/Ti比（>20:1）有利于金红石相的生成。当pH值大于3时,无论H2O₂/Ti比例如何,只能得到锐钛矿相;而pH控制在1左右,且H2O₂/Ti比例在一个合适的值时（10²0,摩尔比）,则有利于板钛矿相的生成。光催化结果表明,球形的锐钛矿粒子具有最好的光催化活性。另一方面,利用PTC前驱体的稳定性,可以控制其反应速度进而通过一步法在低温常压下合成纯的金红石纳米棒,金红石相的生成由PTC前驱体的结构直接决定,没有通过任何过渡相的转换。所制得的金红石纳米棒的粒径可以通过调节前驱体浓度而控制,光催化活性测试表明小粒径的金红石纳米粒子呈现出较好的光催化活性。2、利用SiO₂同TiO₂之间发生的复合作用,制得了一种具有高光催化活性的TiO₂&SiO₂复合溶胶。通过加入一定的表面活性剂和成膜助剂,该溶胶可以应用于不同的建材基底,如玻璃、瓷砖、金属以及塑料基底,并且呈现出良好的亲水性,在室外可以维持三个月以上,可应用于外墙自清洁涂料。而且,将该复合溶胶应用于纺织品表面,呈现出良好的甲醛降解效果。研究了不同纺织品基底的光催化降解效率,结果表明棉布由于表面具有大量的羟基组分,具有最好的甲醛降解效果。在20小时内,对室内甲醛的降解可达到70%以上,甲醛浓度低于2ppm。3、利用PTC体系可低温合成锐钛矿TiO₂溶胶的特性,将所制得的TiO₂溶胶作为柔性DSSC光阳极浆料的成膜助剂,引入到DSSC体系中,研究发现PTC溶胶的加入可以很好的提升所制得柔性染料敏化太阳能电池的性能。当PTC溶胶回流时间为9小时,添加量为10%（体积含量）时,所得的电池性能最好,同未加入PTC溶胶的体系相比,光电转换效率可以提高50%以上。更多还原

【Abstract】 Titanium dioxide nanoparticles have attracted great attention in the semiconductor photocatalysis field due to its wide band gap and good stability. It has wide application for wastewater purfication, air cleaning, anti-bacteria and self-cleaning. Moreover, controllable synthesis of nanoparticles with particular structure and composition is a great research point, as the properties of nano materials can be affected by the particle sizes, morphologies and phases. However, due to the high reactivity of the titanium precursor, it is very difficult for controllable synthesis TiO₂ nanopartilces at ambient conditions. In our work, we utilized a stable water-base peroxo-titanum complex （PTC） as a precursor to controllably synthesize titanium fuctional materials at low temperature, and investigated the structures, properties as well as application as follows.1. We described a systemic approach for preparation of different phases and morphologies titanium dioxide nanoparticles with peroxotitanium complex （PTC） as a precursor by adjusting the system pH value at amident conditions. The pH value and molar ratio have obvious influence on the final phases. Low pH （pH 0） and high H2O₂/Ti molar ratio （> 20:1） are benefit for rutile phase. There is an optimum H2O₂/Ti molar ratio for brookite formation at pH about 1. When the pH value reach to 3 or above, anatase particles are obtained whatever the [H2O₂]/[Ti] ratio is. Photocatalytic properties of different products were measured by decomposing methylene blue. The spherical anatase phase showed higher photocatalytic degradation rates for methylene blue than others. Futhermore, we described a one-step and solution （water-based） synthesis method for preparing rutile nanorods form PTC precursor at 100 oC. In this reaction process, rutile stucture is directly decided by the PTC precursor, without any transition phase. The size of the nanorods could be controlled by simply changing the concentration of the precursor. It is found that the smaller rutile nanoparticles show higher photocatalytic activity.2. SiO₂/TiO₂ composite sol was prepared from the PTC precursor. It showed not only high photocatalytic activity but also hydrophibility. The composite sol can be used for different architectural substrates by adding especially surfactant and assistant agent for about three months at outdoor experiment. Furthermore, the sol showed good activity formaldehyde-decomposing activity when used on texile. We discussed the photocatlytic activity on different substrates. It was proved that the cotton material shown the best activity due to its large amount of surface hydroxyl. The decomposing ctivity can reach 70% and the formaldehyde concentration was less than 2 ppm in 22 hours.3. The anatase TiO₂ sol prepared from Peroxotitanium Complex （PTC） at low temperature was used as the additive for photo-anode of flexible dye sensitized solar cells （DSSC）. It is found that the photoelectric performance of DSSC was obviously increased by 50% with the addition of TiO₂ sol. Furthermore, we investigated the effects of the sol content and reaction time on the photoelectric performance. It is proved that there is an optimal addition value for the DSSC application. When the content （volume） of PTC sol is 10% and refluxing time reaches to 9 hours, the best photoelectric performance is obtained.更多还原