The Synthesis Of Fe³⁺/B Doped TiO₂ Nanotube Arrays And Study On Its Performance Of Photocatalytic Activity

As one of the most potential application of the wide band gaps n-type semiconductor materials, nanoscale TiO₂ light catalyst has attracted much attention and to be a promising green environmental protection catalysts, with the strong oxidation ability, stable chemical properties, high efficiency light catalytic performance, no secondary pollution, excellent efficiency of remove to low concentrations of pollutants and gas phase pollutants, well of adsorption to pollutants. Accordingly, TiO₂ nanotubes array, a kind of the existing TiO₂ form, will have a bright application in photocatalytic degradation, photodissociation water hydrogen production, DSSC, sensor materials et al cause of the more specific surface area, higher photocatalytic activity and stronger adsorption ability. In common with tranditional TiO₂ power, the band gaps of TiO₂ nanotubes semiconductor are much wide (about 3.2 eV) so that only in the UV excitation can display its catalytic activity, the low-usage of sunlight energy, and the electronic– hole pairs which born in the light were easily composite, leading to a lower quantum efficiency. Therefore, doping with ion was introduced in the present work. The primary aim is to improve the efficiency of photocatalyst with efficient separation of electronic-hole pairs by introducing the capture traps to the crystal lattice of TiO₂ nanotubes. Another is to make the wavelength range of excitation light source move to visible light region by decreasing the light energy born electronic.In this work, metal ion Fe and nonmetallic ion B were choosed as the source to modify the TiO₂ nanotube arrays. And the one-step anodic oxidation modification of legal was for preparing metal doped TiO₂ nanotube arrays, nonmetal and metal/nonmetal altogether doped TiO₂ nanotube arrays. The resulting analysis were through electronic microscope (SEM) , X-ray diffraction (XRD), ultraviolet-visible diffuse spectrum (UV - vis), Fourier infrared absorption spectra( FT-IR) etc to characteristic the sample's surface morphology, crystal transformation, crystalling phase composition, visible absorption properties. Afterward, the visible bare catalytic activity of doping modification of TiO₂ nanotubes array was studied, utilized methyl orange as degradation agent simulating the organic wastewater, under visible light irradiation(the sunlight for the light source). The resuls shown that the doped elements and doping amount had a grate effect upon the morphology, crystal and visible catalytic activity of TiO₂ nanotube arrays, and the addition concentration of each doped ion has an optimum value ,the addition concentration is too much or too little will affect its all aspects of performance. Through the modification of the proper proportion of ion doping, the surface morphology of nanotube arrays improved, the average length up to 2μm, the light catalytic performance has been improved, and the light response range had different degrees of expansion. to the visible wavelength range .