预晶核的合成、性质和应用研究

发布时间：2018-06-02 09:27

  本文选题：锆/铪氧簇合物 + 碱金属卤化物簇　； 参考：《山东大学》2017年硕士论文

【摘要】：二氧化锆和二氧化铪具有硬度大、耐高温、良好的化学稳定性等优点,被广泛用于隔热、电子信息、燃料电池及仿生材料等领域。锆/铪氧簇合物不仅可以作为二氧化锆/二氧化铪的分子模型和形成的中间体,还是构筑功能化金属有机框架Zr/Hf-MOFs材料的基本结构单元。溶胶凝胶法是合成二氧化锆/二氧化铪最常用方法,锆/铪氧簇合物作为预成核阶段的纳米簇合物,存在于二氧化锆/二氧化铪形成过程中,因而捕获并解析其晶体结构,对于研究二氧化锆/二氧化铪形成的分子机制具有重要意义。其次,碱金属卤化物广泛存在于自然界中,碱金属卤化物纳米簇合物同样作为预成核阶段的纳米簇合物,是连接微观分子世界和宏观固体材料世界的桥梁,它的研究对于理解溶液成核过程及其成核阶段微观团簇结构具有重要价值。鉴于此,本论文采用溶胶凝胶法,成功获得了二氧化锆/二氧化铪形成中间体—被羧酸基团和硫酸根基团共同稳定的锆/铪氧簇合物;并通过溶液中静电吸引和分子识别相互作用,利用锆/铪氧簇合物成功捕获到预成核阶段能够代表体相晶体结构的碱金属卤化物纳米簇合物。对这些化合物的结构和光谱性质做了充分表征,对形成条件做了详细研究,最后对这些簇合物的超离子导电性和溶液化学做了进一步探索。论文内容分为以下三个部分:第一部分:综述了二氧化锆/铪以及金属氧簇合物的研究进展、种7类及合成方法;总结了文献报道的锆/铪氧簇合物的结构及性质以及碱金属卤化物簇合物研究进展;最后,阐述了本论文选题的科学意义。第二部分:以ZrOC12/HfOC12为前驱体,采用溶胶凝胶法,获得了一个具有风车状结构的新颖的十七核锆/铪氧簇合物;对合成条件做了详细筛选,并在改变条件后获得了一个六核锆/铪氧簇;围绕ZrⅣ离子水解缩聚为Zr02纳米晶的过程,对上述化合物的角色做了详细分析;进一步表征了化合物的结构和光谱性质,并探究了它们的超离子导电性。第三部分:以ZrC14/HfC14为前驱体,通过溶液中静电吸引和分子识别相互作用,采用四核的锆/铪氧簇合物成功从卤化铯(CsCl和CsBr)溶液中捕获到预成核阶段的碱金属卤化物纳米簇合物[Cs8X27]19-(X = Cl,Br),该离子簇跟CsCl晶体的体相结构相同,非常接近于后者的四个晶胞;并对它们进行了详细的结构和光谱表征;最后对它们的超离子导电性和溶液化学做了研究。
[Abstract]:Zirconium dioxide and hafnium oxide have many advantages such as high hardness, high temperature resistance and good chemical stability. They are widely used in thermal insulation, electronic information, fuel cells and bionic materials. Zirconium / hafnium oxide cluster can be used not only as molecular model and intermediate of zirconium dioxide / hafnium dioxide, but also as the basic structure unit of functionalized organometallic frame Zr/Hf-MOFs material. The sol-gel method is the most commonly used method to synthesize zirconium dioxide / hafnium oxide. The zirconium / hafnium oxide cluster, as a nano-cluster in the pre-nucleation stage, exists in the formation of zirconium dioxide / hafnium oxide, so its crystal structure is captured and analyzed. It is of great significance to study the molecular mechanism of zirconium dioxide / hafnium dioxide formation. Secondly, alkali metal halide widely exists in nature, and alkali metal halide nanoclusters are also used as nanoclusters in pre-nucleation stage, which is a bridge between micromolecular world and macroscopic solid material world. Its research is of great value in understanding the microstructure of the solution nucleation process and its nucleation stage. In view of this, zirconium dioxide / hafnium oxide has been successfully obtained by sol-gel method to form zirconium dioxide / hafnium oxide cluster, which is stabilized by carboxylic acid group and sulfate group. Through the interaction of electrostatic attraction and molecular recognition in solution, zirconium / hafnium oxide cluster was used to capture the alkali-metal halide nanoclusters which can represent the bulk crystal structure in the pre-nucleation stage. The structure and spectral properties of these compounds were fully characterized, and the formation conditions were studied in detail. Finally, the superionic conductivity and solution chemistry of these clusters were further explored. The content of this paper is divided into three parts as follows: in the first part, the progress of research on zirconium dioxide / hafnium and metal oxygen cluster, 7 kinds of zirconium dioxide / hafnium and their synthesis methods are reviewed. The structure and properties of zirconium / hafnium oxide cluster and the research progress of alkali metal halide cluster were summarized. Part two: using ZrOC12/HfOC12 as precursor, a novel cluster of zirconium / hafnium with windmill structure was obtained by sol-gel method. A hexanuclear zirconium / hafnium oxide cluster was obtained after changing the conditions, the roles of the compounds were analyzed in detail around the process of hydrolysis and condensation of Zr 鈪，

本文编号：1968263