Research On Fabrication Of Rare Earth-Doped Titania Nanofibres Via Electrospinning And Their Photocatalytical Properties

Nano-TiO₂ photocatalyst to degrade contaminants is a novel promising environmental-friendly catalytic technology.Being new-typed promising photocatalysts, one-dimensional pure TiO₂ nanofibers and rare earth-doped TiO₂ nanofibers photocatalysts have attracted much concern from the scientists.In recent years,scientists have paid much attention to electrospinning technique,and it has become one of the important methods to prepare inorganic oxide nanofibers.Hence,it will be a very important subject of study to fabricate pure TiO₂ nanofibers and rare earth-doped TiO₂ nanofibers by electrospinning and to investigate their photocatalytic properties.In this dissertation,sol-gel method was applied to prepare the precursor solution of a certain viscosity,and electrospinning technique was used to fabricate PVP/[Ti(SO₄)₂+Gd(NO₃)₃],PVP/[Ti(SO₄)₂+La(NO₃)₃],PVP/[Ti(SO₄)₂+Y(NO₃)₃]and PVP/Ti(SO₄)₂ composite fibers,and the optimum preparative conditions were obtained.TiO₂, Gd/TiO₂,La/TiO₂ and Y/TiO₂ nanofibers were prepared by calcination of the above relevant composite fibers.The samples were characterized by field emission scanning electron microscope(FESEM),transmission electron microscope(TEM),fourier transform infrared spectrometer(FTIR),x-ray diffraction(XRD) and thermal analysis(TG-DTA).The results showed that composite fibers had good dispersion and large aspect ratio,and the average diameter was 150-200nm.The mean diameter of rare earth-doped TiO₂ nanofibers was in the range of 50-75nm,and the length was more than 300μm.The photocatalytic activities of prepared TiO₂,Gd/TiO₂,La/TiO₂ and Y/TiO₂ nanofibers were studied by taking methyl orange,rhodamine B,phenol and photographic waste liquid as degradation agents,respectively.The results showed that concentration of the catalyst,pH of the degradation solution,the doped amount of rare earth and calcination temperature had some influences on photocatalytic properties.By the analysis of ultraviolet and visible spectra(UV-Vis),it was found that all the four kinds of photocatalyst exhibited certain photocatalytic activities to the different degradation agents.The photocatalyst doped with 1.5%Y³⁺(in mole fraction,the same as below) can degrade the rhodamine B effectively, while nanofiber-structured TiO₂ doped with 1.0%Gd³⁺ displayed excellent activitiies in degrading the phenol,methyl orange and photographic waste liquid.Therefore,the nanofiber-structured TiO₂ doped with the different rare-earth oxides photocatalysts possessed the selective degrading activity for the different organic compounds.