| At present, the environmental pollution have been getting more and more serious, especially, the water pollution. It has become one of the major environmental problems. In order to improve water quality, it is imperative to reduce industrial pollution and pollutant content of industrial wastewater. As a new technology for water purification, photocatalysis technology has attracted much attention due to its mild reaction condition, low energy consumption without secondary pollution, and it could decompose the contaminant to stable compound at ordinary temperatures and pressures. As a kind of semiconductor with developed nanostructure, TiO2 nanotubes become the most promising photocatalyst and an important development direction of photocatalytic technology, because of its mechanical stability, corrosion resistance and porous surface nanomorphology, and other excellent properties of TiO2.In this thesis, the modification of TiO2 nanotubes was studied. Ti mesh was used as the base material, WO3 was used as the dopant of Ti mesh supported TiO2 nanotubes (TM), and then Ti mesh supported WO3/TiO2 nanotubes composite (WTM) was fabricated via anodic oxidation and electrodeposition methods. And then physical properties of all the samples were investigated by X-ray diffraction, Scanning electron microscope, UV-vis spectrophotometer. The photocatalytic activity of the material was tested by photocatalytic degradation activity of the methylene blue (MB) degradation under visible light.Firstly, TM were prepared by using anodic oxidation Ti mesh in a solution consisted of ethylene glycol, NH4F and H2O at a constant potential, and then annealed at 500℃. The influence of different anodic oxidation voltages and times on the surface morphology of the samples was investigated. After characterization of these samples, it was found that TiO2 nanotubes were arranged highly orderly when TM prepared at 30V for 30min, and TiO2 transferred to anatase type TiO2 after annealed at 500℃.Secondly, WTM was prepared by anodic oxidation coupled with electrodeposition. According to the characterization results, WTM was coated with a layer of WO3 particles, and WTM showed relatively high absorbance both in UV and visible region. For photocatalytic degradation of MB under visible light for 120min, WTM presented degradation rate of 72%, and its degradation rate with string MB solution was 12% higher than that without string, both more higher than the Ti plate supported WO3/TiO2 nanotubes composite. After cleaning WTM, the cycling life of WTM had been tested, the results showed that all the cycle efficiencies were 69%,92%, and 93%, respectively.Finally,The WTM coated with different content of WO3 had been prepared by adjusted current density during electrodeposition progress. The influence of electrodeposition current density on the crystal structure, apparent morphology, and MB degradation rate of WTM had been studied. The results showed that both the content of WO3 and absorbance visible region increased with the increasing of the electrodeposition current density. After the test of MB degradation, WTM2 prepared at 8mA/cm2 presented degradation rate of 85%, was 14% higher than WTM1 prepared at 4mA/cm2 and 3% higher than WTM3 prepared at 16mA/cm2. And in the test for the first time cycle efficiency of MB degradation,the first time cycle efficiencies of MB degradation for WTM1, WTM2, WTM3 were 90%,86%,80%, respectively. Although initial cyclic efficiency of WTM2 was lower than WTM1, but degradation rate of WTM2 for the second time were higher than WTM1 of 9% and WTM3 of 7%. Comprehensive consideration, the current density of 8mA/cm2 for WTM optimum eletrodeposition current density. |
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