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The Preparation And Photocatalytic Performance Research Of Long After-glow Phosphor Coupled With Titanium Dioxide Materials

Posted on:2017-12-13Degree:MasterType:Thesis
Country:ChinaCandidate:C GongFull Text:PDF
GTID:2311330503457141Subject:Chemical Engineering and Technology
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With the continuous development of science and technology, more and more people have higher requirement of multifunctional composite materials. TiO2 has photocatalytic activity under UV light as a kind of good photocatalyst. TiO2 is widely used in the field of photocatalysis, but its single photocatalytic performance has not satisfied the need of people. The composites of TiO2 photocatalyst coupled with long afterglow luminescent materials, keep the photocatalytic activity not only under the visible light irradiation but also in the dark. In addition, this kind of composite material has strong antibacterial properties. The long persistence materials in the composite materials can absorb light energy and storage under the light irradiation, then release the energy in dark. the wavelength of the long afterglow luminescent materials emitted is shorter than the wavelength of TiO2 absorded, so the TiO2 has photocatalytic activity. Meanwhile, the composite has the photocatalytic activity under dark. Most long afterglow materials emit visible light, but the pure TiO2 photocatalyst only absorbs the UV light. We need to modify both TiO2 and long afterglow material in order to match the two wavelengths.This paper mainly reasearch the combustion method of long afterglow luminescent materials and their luminescence properties. Then the composite materials are prepared by sol-gel method, in the process of preparation, metal ions doping into the TiO2 catalyst. The degradation of the MO and antibacterial properties of the composite materials are researched. Finally, doping metal ions, and then prepared by sol-gel step out composite materials and observed under the condition of light the photocatalytic degradation of methyl orange and antibacterial properties. Then, using the method of mechanical grinding, synthesize the composite materials and research the influence of plasma Ag@AgX doping into TiO2 for the composite materials' photocatalytic performance.This thesis mainly includes the following three aspects:?1? Different kinds of long persistence materials prepared by combustion method. MgAl2O4:Pr3+,Dy3+ has the strongest emission fluorescence intensity of all according to the fluorescence spectra and the emission wavelength is 562 nm. From the XRD characterization of MgAl2O4:Pr3+,Dy3+, we find that it is MgAl2O4 monoclinic crystal phase. On this basis, we research the factors which influence the luminous intensity in prepararing long afterglow luminescence materials by combustion method. magnesium aluminum ratio of 1:2, 5%Dy3+, 10%H3BO3, 5 times CO?NH2?2 of metal ions are added during preparation process of long afterglow material, the fluorescence intensity is strongest.?2? The composite materials of long afterglow luminescence materials MgAl2O4:Pr3+,Dy3+ and Cr,Co,Ni doping into TiO2 are prepared by the sol-gel method. Metal ion doping into TiO2 photocatalyst enhance light response range and the TiO2 light absorption range from 380 nm red shift to 650 nm. Metal ions doping into TiO2 absorb the light which is emitted by long afterglow material MgAl2O4:Pr3+,Dy3+ in dark and MgAl2O4:Pr3+,Dy3+ emission wavelength was 562 nm, so the composite materials keep photocatalytic activity in dark. The composite materials' ability of degradation of methyl orange are researched under xenon lamp?? >400 nm? illuminatting 30 min and reacting 90 min in the dark. MgAl2O4:Pr3+,Dy3+/Cr-TiO2 composite has the best degradation rate for methyl orange of the three composites and the degradation rate is 71.8%. In addition, the composite materials have good antibacterial properties. The composite materials is a kind of relatively stable photocatalytic materials according that they maintain high catalytic activity through six times cyclic degradation methyl orange.?3? Long afterglow luminescence materials and Ag@Ag X doping into TiO2 are prepared by Combustion method and Hydrothermal method respectively, then MgAl2O4:Pr3+,Dy3+ /Ag@AgX-Cr-TiO2?X=I,Cl,Br? are obtained by mechanical grinding method. Plasmon resonance effect of Ag@Ag X expand light absorption range of TiO2 catalyst and restain recombination of photoproduction electronic and optical cavity, so the photocatalytic activity of TiO2 improves. In the dark light, plasma doping into TiO2 photocatalyst has better ability to absorb the light which is emitted by long persistence materials, improves photocatalytic activity of the composite materials. and under the condition of light composite photocatalytic activity increase. The degradation rate of methyl orange for composite material MgAl2O4:Pr3+,Dy3+ /Ag@AgI-Cr-TiO2 is as high as 87.66%. The author found out that Ag@AgX doping into the composite materials strengthen the composites' antibacterial properties according to the antibacterial experiment.
Keywords/Search Tags:combustion method, long afterglow materials, TiO2, Metaldoping, Ag@AgI plasma, resonance effect, composite materials
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