Preparation And Properties Of S/N Co-doped TiO₂Nanotube Array

Titanium dioxide has become some kind of very important functional materialdue to its unique gas-sensitive and photoelectric conversion propreties. However,the application of TiO₂has been greatly limited because of its large band gap andhigh active point defects which appear during the preparation and crystallization aswell as the secondary pollution. Therefore, the preparation of TiO₂nanotube arraysand improvement of the performance has great practical application value.In this paper ammonium fluoride, water and ethylene glycol was used as theelectrolyte, titanium dioxide nanotube array thin films were prepared byanodization. The TiO₂thin films were characterized using scanning electronmicroscopy （SEM）, X-ray photoelectron spectroscopy （XPS） and X-ray diffraction（XRD）.The surface morphology and dimensions of TiO₂nanotube arrays werediscussed.N doped and S/N co-doped TiO₂nanotube array thin films were preparedby annealed under the ammonia atmosphere and fully dipped into thiourea solution.The effect of doping elements were studied.The results showed that the TiO₂nanotube arrays with120～140nm in diameterand approximate40μm in length were prepared uniformly on Ti sheet. The sizeparameters of nanotubes and the concentration of electrolyte were changed regularly andnanotube controllable preparation were achieved by controling the different experimentalparameters. S and N elements co-doping were achieved by substitutional doping andinterstitial doping. In doping process the phase change temperature of TiO₂was reduced,and the micromorphology of TiO₂nanotubes array was not changed. The catalyticactivity of TiO₂was.ignificantly improved by doping process, after that the sampleobtained the obvious response to visible light.