Study On The Preparation, Modification And Photoelectric Properties Of Titanium Dioxide Nanotube Arrays

Because of the serious environmental and energy depletion problems resulting from the combustion of fossil fuels, modern society has been seeking for a new technology to effectively address the issue. Two primary research direction are converting light energy into chemical energy and the degradation of organic pollutants by solar photocatalytic. The key link is exploitation of cheap and efficient photoelectrocatalysis materials. TiO2 nanotube arrays express several unique properties of highly degree of order and high specific surface area. So TiO2 nanotube arrays have been researched widely.In this paper, TiO2 nanotube arrays are prepared by anodization in the ethylene glycol with ammonium fluoride and small quantities of water. The prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM),energy dispersive spectrometer (EDS) and photoelectrochemical test and so on. These tests can observe the influence of preparation condition to the morphology and crystalline natures of the samples, chemical stability and photoelectric property. The optimum conditions for the preparation of TiO2 nanotube arrays are determined through photoelectric conversion efficiency and removal rate of phenol. They are oxidized at voltage of 60 V in the electrolyte with 0.2 mol L-1 ammonium fluoride and calcined at 500 ? for 1 h. At this preparation conditions, the photoconversion efficiency can reach 12.26%, the removal rate of phenol is 48.3%, at the same time, chemical stability of sample is the highest.Photoelectric property of TiO2 nanotube arrays can be improved though doping and decoration of other elements. In this experiment, the samples of Ag/TiO2 are prepared by photo-reduction in the methyl alcohol under UV illumination. The optimum conditions for the preparation of Ag/TiO2 are 0.004 mol L-1 AgNO3,illumination time of 12 h and UV light power of 8 W, respectively. At the optimum conditions, the photoelectric conversion efficiency can reach 14.93%, the removal rate of phenol is 55.36%. The electrodes of TiO2/Sb-SnO2 are prepared by the decoration of Sn-Sb sol on the TiO2 surface. The best coated weight of Sn-Sb sol is 8 layers. At this time, the photoconversion efficiency can reach 15.24%, the removal rate of phenol is 75.36%. The photoconversion efficiency can increase to 15.61% and 16.42%, the removal rate of phenol can increase 77.63% and 82.51% by addition of Ni and Ru in the Sn-Sb sol.