Study On Preparation And Modification Of Titanium Dioxide Nanotubes And Their Photocatalytic Performance

Titanium dioxide?TiO₂?is a broadly attractive semiconductor material due to its great physical and chemical stability,low cost,non-toxicity,high photocatalytic activity and excellent photoelectrochemical performance.However,the large band gap?3-3.2 eV?of TiO₂ limits its response in visible region.It is necessary to dope and modify TiO₂,in order to improve its response in visible region and utilization of the sunlight.In this dissertation,the highly ordered TiO₂ nanotubes were prepared by electrochemical anodization of Ti foil.Similarly,the Cu-Ti-O nanotubes were prepared by electrochemical anodization of copper titanium alloy?CuTi?foil to obtain the Cu ions doping.Cu₂ O was prepared by DC reactive magnetron sputtering.Subsequently,it was deposited on the surface of TiO₂ nanotubes,which achieved the modification with semiconductor composites.Methyl orange?MO?is a kind of common dye and the decolorization effect of its aqueous solution can be used to measure the photocatalytic performance.The highly ordered Ti O₂ nanotube arrays were prepared by electrochemical anodization of Ti foil.The influence of different process parameters on the morphology of TiO₂ nanotube arrays was studied.Scanning electron microscopy?SEM?was the mian characterization method.Temperature,voltage,anodic oxidation time and the organic acid were studied to explain their influence on the morphology in theory.Thus,the structure and size of TiO₂ nanotubes could be controlled by changing the process parameters.Cu-Ti-O nanotubes were prepared by electrochemical anodization of CuTi alloy foil,which achieved the Cu ions doping.They were characterized by X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?and UV-Vis spectrophotometer.The photocatalytic activity was measured by the degradation rate of MO under ultraviolet light supplied by a mercury lamp.The result showed that the absorption band edge of Cu-Ti-O nanotubes could be extended to 450 nm,but the photocatalytic activity was not improved.Cu₂O was deposited on the surface of TiO₂ nanotubes by DC reactive magnetron sputtering.A series of instruments and equipments were used to characterise Cu₂O-TiO₂ nanotubes and the optimal parameters were obtained.The result showed that the optimal sputtering power,sputtering pressure,sputtering time and oxygen ratio?Ar:O₂?were 76 W,1.0 Pa,20 s and 22:1,respectively.The optical absorption band edge of Cu₂O-TiO₂ was extended to 450 nm.With the optimal preparation conditions,a 94.4% of photocatalytic efficiency for the degradation of methyl orange could be achieved within 120 min under a Xenon lamp irradiation.The photocatalytic activity was improved by 1.14 times?under the same condition,a 44% of photocatalytic efficiency of TiO₂ nanotubes for the degradation of methyl orange could be obtained within 120 min?.