摘要多金属氧酸盐，具有独特的结构特点和丰富的光催化活性，在去除水中有机 污染物及过渡金属离子的领域被广泛研究。大多数多酸盐的光催化性质与半导体 催化剂光解有机化合物的作用机理、中间产物及最终光降解产物相似。然而， HOMO-LUMO 之间的宽频带的缺点导致其低可见光催化活性和在溶液中的高溶 解度导致的低回收率阻碍了它们潜在的应用。许多研究人员已经采取措施，如掺 入非金属材料和一些抗紫外有机聚合物。这些混合物克服了回收率方面的问题， 但仍然有其它的缺陷，如活性受限或者反应中不稳定。另一方面,染料敏化从而 拓宽吸光范围至可见光区也是一个可行的方法。83307

本文使用 NiCl2·6H2O、AgNO3、Co(NO3)2·6H2O 提供过渡金属，尝试不同有 机配体，改变体系 pH，利用水热法合成出 6 种基于多酸的无机-有机杂化材料：[Ni(2,2’-bpy)3]3[P2W18O62] (2,2’-bpy= 2,2’-bipyridine) (1) [4,4’-bpy][NiPW11O62]（4,4’-bpy= 4,4’-bipyridine）(2) [Ag(4,4’-bpy)]5[P2W18O66] (3)[Co(4,4’-bpy)4](H2O)2[PW12O40]2 (4)(4,4’-bpy)(H2O)[H3PW12O40]2 (5)(4,4’-bpy)2(C3H4N2)[H6P2W18O62] (6)单晶 X-射线衍射分析表明，化合物 1、3 为过渡金属与 Wells-Dawson 型多 酸阴离子配合的杂化化合物；化合物 2、4 为过渡金属与 Keggin 型多酸阴离子配 合的杂化化合物；化合物 5、6 为含氮有机配体与多酸模块构筑的超分子化合物， 其中化合物 5 中的多酸模块为 Keggin 型，化合物 6 中的多酸模块为 Wells-Dawson 型；对化合物 1、3、4 进行了红外测试；对化合物 1 进行了紫外-可见漫反射测 试。由于时间不足的原因，本文只研究了化合物 1 光催化降解甲基橙染料的性质， 讨论了反应条件对光催化效果的影响并提出了可能的反应机理。测试表明化合物

1 具有非常优秀的可见光催化活性，且容易回收利用。其余化合物有关光催化性 能的研究将在以后为大家报道。

毕业论文关键词：多金属氧酸盐，光催化，金属配合物，水热合成

Abstract Polyoxometalate (POM) has been extensively studied for the removal of organic pollutants or transition metal ions from water。Many of those POM share similar photochemical characteristics as semiconductor photocatalysts in terms of the overall mechanism of photodecomposition of organic compounds, the intermediate species and the final photodegradation products。The charge-transfer excited state (POM*) with strong oxidising properties can direct oxidize the target pollutant, or react with water or other electron donor to generate occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) leading to low visible-light photocatalytic activity and high solubility in solution making them difficult recovering and recycling impede their potential applications。 Many researchers have made efforts in order to resolve the problems。 Incorporation of homogeneous POMs with support materials and some organic polymers with UV light resistance has been extensively investigated。Those hybrids overcome some difficulties in recovering and recycling, but these methods have other shortcomings such as limited activity or stability during the reaction。On the other hand, dye sensitization is an established means to extend absorbance to the visible region。

In this paper, we use NiCl2·6H2O,AgNO3,Co(NO3)2·6H2O to provide transition metals, trying different organic ligands and changing the pH, using hydrothermal method to synthesize six kinds of inorganic-organic hybrid materials based on POMs:

[Ni(2,2’-bpy)3]3[P2W18O62] (2,2’-bpy= 2,2’-bipyridine) (1)

[4,4’-bpy][NiPW11O62](4,4’-bpy= 4,4’-bipyridine) (2)

[Ag(4,4’-bpy)]5[P2W18O66] (3)

[Co(4,4’-bpy)4](H2O)2[PW12O40]2 (4)