钛氧簇合物的合成及性质研究

发布时间：2018-03-10 04:40

本文选题：钛氧簇合物　切入点：掺杂　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：二氧化钛是最重要的半导体材料之一,且应用广泛。然而带隙较宽、只能吸收紫外光这一性质限制了其对太阳光的利用效率,为此科学家们围绕通过金属或非金属掺杂来改善其光吸收和光催化性质做了大量工作。另一方面,在染料敏化太阳能电池中,染料配体到二氧化钛的光致界面电荷转移是制约太阳光量子效率的关键步骤,因此界面结构和光致界面电荷转移动力学之间的构—效关系是该领域的关键问题。由于二氧化钛的结构复杂,存在大量缺陷和表面活性位点,掺杂离子和配体在二氧化钛体相或表面的化学环境(结构)很难精确获得,从而导致构—效关系难于建立。钛氧簇合物被认为是分子型的钛氧化物,且其晶体结构能够准确表征。因此,合成钛氧簇合物、表征其单晶结构、并研究其光吸收和光催化性质,对于深入理解二氧化钛的结构与光吸收、光催化性质之间的构—效关系具有重要的参考价值。本论文中针对以上问题,合成了一系列金属掺杂和表面配体功能化的钛氧簇合物,表征了晶体结构,在此基础上研究了元素掺杂和表面修饰对钛氧簇合物性质的影响。论文内容分为以下三个部分:第一部分,对二氧化钛的合成方法、表面修饰对于二氧化钛性质的影响、以及金属氧簇合物的种类和合成方法进行了综述;对文献中钛氧簇的结构和性质进行了总结;最后,对本论文选题的科学意义及思路进行了阐述。第二部分,制备了一系列同构的、掺杂不同元素的钛氧簇合物,并研究了金属离子掺杂对于钛氧簇合物光吸收和光催化性质的影响。我们采用控制水解法,分别合成了过渡金属、闭壳层金属和钛空位掺杂的钛氧簇合物,并通过单晶X射线衍射准确表征了其结构。对其性质的研究表明,Co和Ni的掺杂尽管能够提高钛氧簇合物对太阳光的吸收,但是导致了钛氧簇合物紫外光活性的明显降低。与此同时,引入钛空位尽管不会提高钛氧簇合物的光吸收性能,但能提高钛氧簇合物对太阳光的利用效率。本章对于高催化活性的二氧化钛纳米材料的合成具有一定指导意义。第三部分,制备了一系列表面键合邻苯二酚类配体的钛氧簇合物,并表征其结构、光谱性质、配体键合模式和光电性质。我们采用溶剂热和表面配体交换方法合成了含有不同钛原子数的表面邻苯二酚类配体功能化的钛氧簇合物,并表征了其晶体结构。对其性质的研究表明,邻苯二酚类配体在钛氧簇合物表面存在多种键合模式,且邻苯二酚类配体到钛氧骨架的强烈电荷转移能够提高钛氧簇合物的可见光吸收性质。本章中对于单晶结构和电荷转移的研究,对于理解染料在二氧化钛纳米粒子表面的键合模式以及体系的界面电荷转移过程具有重要的参考价值。
[Abstract]:Titanium dioxide is one of the most important semiconductor materials, and it is widely used. However, the wide band gap limits its utilization efficiency of solar light because it can only absorb ultraviolet light. For this reason, scientists have done a lot of work on improving their photoabsorption and photocatalytic properties through metal or non-metallic doping. On the other hand, in dye sensitized solar cells, The photoinduced charge transfer between dye ligands and TIO _ 2 is a key step to restrict the quantum efficiency of solar light. Therefore, the structure-activity relationship between interface structure and photoinduced charge transfer kinetics is a key problem in this field. Due to the complex structure of titanium dioxide, there are a large number of defects and surface active sites. It is difficult to obtain the doping ions and ligands in the chemical environment (structure) of TIO _ 2 body or surface, which makes the structure-activity relationship difficult to establish. And the crystal structure can be accurately characterized. Therefore, the synthesis of titanium oxide cluster, characterization of its single crystal structure, and study of its photoabsorption and photocatalytic properties, for in-depth understanding of the structure and light absorption of titanium dioxide, The structure-activity relationship between photocatalytic properties has important reference value. In this paper, a series of metal-doped and functionalized titanium oxide clusters were synthesized, and the crystal structure was characterized. On this basis, the effects of element doping and surface modification on the properties of titanium oxide cluster were studied. The content of this paper is divided into three parts: the first part, the synthesis method of titanium dioxide, the effect of surface modification on the properties of titanium dioxide, and the effect of surface modification on the properties of titanium dioxide. The types and synthesis methods of the metal oxygen clusters are summarized. The structure and properties of titanium oxide clusters in the literature are summarized. Finally, the scientific significance and ideas of this thesis are described. A series of isomorphic titanium oxide clusters doped with different elements have been prepared, and the effects of metal ion doping on the photoabsorption and photocatalytic properties of titanium oxide clusters have been studied. The structure of titanium oxide cluster doped with closed shell metal and titanium vacancy has been accurately characterized by single crystal X-ray diffraction. The results show that the doping of Co and Ni can improve the absorption of titanium oxide clusters to the sunlight. At the same time, the introduction of titanium vacancy does not improve the photoabsorption of the titanium oxide cluster, but it leads to a significant decrease in the UV photoactivity of the titanium oxide cluster, while the introduction of the titanium vacancy does not improve the photoabsorption of the titanium oxide cluster. However, it can improve the utilization efficiency of titanium oxide clusters for sunlight. This chapter has certain guiding significance for the synthesis of titanium dioxide nanomaterials with high catalytic activity. A series of titanium oxide clusters with surface bonded catechol ligands were prepared, and their structures and spectral properties were characterized. Ligand bonding mode and optoelectronic properties. Surface catechol ligands with different number of titanium atoms were synthesized by solvothermal and surface ligand exchange. The crystal structure was characterized. The study of its properties showed that catechol ligands had many bonding modes on the surface of titanium oxide clusters. And the strong charge transfer from catechol ligands to the titanium oxygen skeleton can improve the visible light absorption properties of titanium oxide clusters. It has important reference value for understanding the bonding mode of dyes on the surface of TiO2 nanoparticles and the interfacial charge transfer process of the system.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4

【相似文献】