Synthesis,Structures And Photoelectric Properties Of Transition' Metal Doped Titanium Oxo-Clusters

Titanium oxide materials are widely applied in photodegradation,photocatalysis,energy storage,etc.especially in photoelectric conversion.In the past decade,titanium oxo clusters(TOC)have attracted wide research interest as a structure and reaction model of TiO2 nanoparticles.Their precise structural information provides the basis for the study of structure-property relationships and photocatalytic mechanisms in these systems.Doping of transition metals or modification of photosensitive organic ligands can change the energy band structure of the TOCs,so that they can be excited at low energy.At present,the studies on doped TOCs are still fragmentary,and most of the studies on heterometallic TOCs have focused on some simple organic carboxylate ligands.The work of this thesis is mainly to explore the synthesis and structure analysis of TOCs modified with both transition metals and photosensitive materials,and to analyze the synergistic effect of the two components in photoelectric conversion.The work of this thesis consists of the following three parts:(1)In chapter 1,the current research of TOCs were introduced,especially the metal-dopedTOCs in recent years;the applications of TOCs in in photocatalysis,photoelectric conversion,and fluorescence were outlined.(2)In chapter 2,compounds containing different transition metals and catechol were synthesized:[Ti12M2O10(OEt)22(Cat)2(BA)4](M=Co,Mn,Ni,H2,Cat?catechol,HBA?benzoic acid).Unlike most spherical TOCs,structures of compounds 2-4 have a unique layer structure.The photoactive electrode was prepared by immersing a mesoporous titanium dioxide electrode plate in a solution of the TOCs,and the photocurrent response characteristics of the electrodes were studied.The results show that the photocurrent density of metal-doped clusters is higher than that of undoped clusters.The redox-active Co(II)-doped cluster showed the highest photocurrent density.(3)In chapter 3,M-bpy(bipyridine)moieties were successfully introduced into TOCs by the solvothermal method to obtain the compound[Ti17O28(O'Pr)16(Mbpy)2](M=Co,Mn,Ni,Cu).The structure of these compound can be considered as a Ti17 cluster modified by two M-bpy complexes.The coordination of M-bpy changes the band structure of the Ti17 clusters and increases their absorption wavelength range.Consequently,the titanium oxide material can be excited at low energy(4)In chapter 4,the 5-sulfosalicylic acid was successfully introduced into the TOCs by solvothermal method,and a series of compounds were obtained:(Et3NH)5[Ti(ssal)3],[Ti4(Hssal)2(OiPr)2(acac)2],[Ti6O3(ssal)2(OiPr)12(DMF)2],[Ti7O3(H3ssal)2(OiPr)12(Cat)].Their structure information were obtained by X-ray single crystal diffraction,and the coordination styles of the 5-sulfosalicylic acid are compared and summerized.