Of Tio <sub> 2 </ Sub> Nanotube Arrays Anodic Oxidation Was Prepared, Modified And Photoelectrocatalytic Performance Study

TiO2 nanotube arrays have a potential and attractive application in many areas, such as photocatalytic degradation of pollutants, photolysis of water into hydrogen and solar cells. In this paper, some experimental investigations are made in detail, including the preparation of TiO2 nanotube arrays by anodic oxidation, the modification of prepared the TiO2 nanotube arrays by semiconductor nanocrystals, the preparation of composite TiO2 nanotube arrays with deposition of TiO2 and CdS nanoparticles by ultrasonic deposition method, and a systematic study of photoelectrocatalytic properties of the pure and composite TiO2 nanotube arrays. The important results obtained from those researches are listed as follow.(1) Prepare TiO2 nanotube arrays on titanium substrate by anodic oxidation in a highly ordered, as well as controllable length and diameter dimensions; adopt improved ways of secondary growth to prepare TiO2 nanotube arrays without substrate; use low temperature annealing methods to control the crystal structures of TiO2 nanotube arrays, for example, through 500℃annealing treatment, we can achieve anatase-based mixed crystal structure with a high catalytic activity.(2) Take the degradation of methyl orange as example to systemstically evaluate the photoelectric catalytic performance of TiO2 nanotube arrays prepared by anodic oxidation, finding that thses TiO2 nanotube arrays have superior photoelectrocatalytic performance than those prepared by hydrothermal method and commercial TiO2 nanocrystalline. Repeated degradation experiments also showed that TiO2 nanotube arrays prepared by anodic oxidation had good reusability.(3) Take the high-efficiency ultrasonic method to deposite nanocrystalline TiO2 coated with PEG into the channels of TiO2 nanotube arrays. The deposition time was only 10s, and the nanotubes did not clog or collapse after deposition. We found that the optical current density of TiO2 nanotube arrays with deposition of TiO2 nanoparticles was significantly higher than those without sediment samples, and the photoelectrocatalytic efficiency of methyl orange was increased by 10%.(4) In order to achieve TiO2 nanotube arrays corresponding to visible light, TiO2 nanotubes were assembled with visible light sensitizer CdS nanocrystallines on the surface by using ultrasonic reaction deposition method, finding that the absorption spectrum happenned red shift from 387nm to 535nm. Thus can be applied in the visible light photocatalytic activity and sensitized solar cells. Deposition time is only 20s, greatly simplifying the repeated immersion method.