Synthesis And Properties Of Lanthanide Elements Doped And Polyacid Titanium Oxo Clusters(TOCs)

Titanium oxide materials have been widely used in photodegradation.photocatalysis and photoelectric conversion.Great attention has been paid to lanthanide elements doped and organic functional molecules modified titanium oxo clusters,owing to their excellent photoluminescence and photocatalysis properties.Titanium oxo clusters are analogous to titanium oxide but molecular compounds with discrete structures.They are intermediates in the hydrothermal synthesis of TiO2 nanomaterials.Their definite structures provides the basis for the further study of titanium oxide materials.Thus,the research on the synthesis,structures and properties of titanium oxide clusters has attracted the attention of scientists.So far,the study of titanium oxide clusters has mainly been focused on the introduction of organic functional ligands and doping of transition metals.Nevertheless,lanthanide elements doped titanium oxo clusters have rarely been reported and most of them are small clusters(nTi<10).Moreover,except their syntheses and crystal structure characterization,their properties in applications were hardly studied.In this paper,new types of organic-inorganic hybrid titanium oxide clusters were synthesized by using lanthanide elements and organic small molecule ligands and the optical and catalytic properties of lanthanide ions doped titanium oxide clusters were studied.The main work of this paper includes the following three aspects:Firstly,the development and application of titanium oxide clusters in recent years are briefly introduced and the applications of titanium oxide clusters in photocatalytic degradation and photoelectric conversion are also summarized.In chapter 2,three lanthanide elements doped TOC compounds[LnTi11O16(NO3)2(OiPr)17]·3H2O[Ln = Sm(1),Eu(2),Gd(3)]are prepared in situ solvothermal synthesis.The cluster structures of these compounds adopt a LnTi11 cage structure.Compound 2 exhibits characteristic fluorescence of Eu(Ⅲ)and the emission can be decreased upon irradiation and recovered by air oxidation,which is attributed to the photo-induced Ti(Ⅲ)ion of the oxo-TiO cluster.Compound 2 might be used as a precursor for application in fluorescence labelling and directed catalysis.The substrates prepared by compounds 1-3 have good properties of photocatalytic degradation of dyes and the fluorescence intensity of 2 can be significantly increased by treating with 1,10-phenanthroline.This is a pioneering exploration of the application of lanthanide doped titanium oxide cluster.In chapter 3,compounds[Ti10O3(BTCA)(OiEt)17]·3H2O(4)and[Ti10O4(CHDA)4(OiPr)17]·3H2O(5)with novel structures are successfully prepared in situ solvothermal synthesis through introducing 1,2,3,4-butane tetracarboxylic acid and 1,4-cyclohexane diacid into titanium oxide clusters.Compound 4 has the characteristics of rapid gelation and photochromic.The film prepared by CH2Cl2 solution of compound 4 is hollow micro tube with the length of 10μm.Compounds 4 and 5 can be used in photocatalytic degradation of organic dyes.The organic-inorganic hybrid film electrodes prepared by using the crystals as the precursors have good photoelectric response properties.