Preparation And Catalytic Activity Of CuS Nanoparticles Sensitized Titania Nanotube Arrays

Titania nanotubes own simple preparation methods, low cost, high specific surface areaand so on, it has been widely applied in the dye-sensitized solar cells(DSSC), water photolysis,ultraviolet photodetector, photocatalysis ect. Due to wide-gap band up to3.2eV, it restrictsN-type TiO2only excited by ultraviolet light accounting for only5%of the total solar energy,However, the photo-induced electron-hole pairs also readily recombine in order to restricttheir application. The titania nanotubes sensitized by narrow bandgap semiconductor(CdS、CdSe、CuS ect.) are expected to reveal dramaticlly high visible light absorbing capacity andsuppression of electron-hole recombination. Thus the systematical studies on the preparationand characterization of TiO2nanotube arrays (TNTAs) and their compositions have bothscientific and engineering significances. In this thesis, the main contents are as follows:Firstly, we synthesized uniform TNTAs by simple anodic oxidation method at roomtemperature, and investigated the influence of anodic oxidation time, anodic oxidation voltageand calcination temperature on their morphology and crystalline structure, experimentalresults indicated that the factors dramaticlly influenced their morphology and crystallinestructure. Also, we studied the effect of secondary anodic oxidation on the morphology ofTNTAs. Finally, The formation and photocatalytic mechanism of TNTAs were detailedlydiscussed.Secondly, the uniform and monodispersed CuS nanoparticles were readily prepared innon-toxic oleic acid/liquid paraffin system using low-cost cupric oxide and elemental sulfuras the precursors at120℃. The influences of different molar ratio of Cu2+: S2-and differentreaction time on the morphology, crystalline structure, optical properties have beeninvestigated. Meanwhile, we found that different cleaning agents played an important role onthe eventual morphology. Finally, the formation mechanism was proposed.Thirdly, we prepared CuS/TNTAs using two different methods in the chapter: one is thatwe directly deposited CuS NCs pretreated in the third chapter on TNTAs by sonic oscillation,the other is that the TNTAs were immersed into the mixed solution of Cu and S precursorsand hydrothermally reacted for10h at100℃in the oven to obtain the CuS/TNTAs. Theinfluences of sensitization time on the morphology, crystalline structure and optical propertieshave been investigated. UV-Vis tests showed that the composite material can enhance thevisible light absorption. Compared with TNTAs unsensitized, the photocatalytic degradationrate of Rhodamine B significantly improves, the sample with reaction time of10h showed thebest photocatalytic efficiency of RhB solution about71.3%in one hour. Finally, thephotocatalytic mechanism was detailedly discussed.