Fabrication Of TiO₂Nanotube Arrays Modified With Semiconductor And Their Application

Titanium dioxide （TiO₂） is the most promising photocatalyst for degradation oforganic pollutants by utilizing sunlight in the environment pollution field. However,TiO₂with the wide band gap can only absorb ultra-violet（UV） light, which limites theutilization of the solar. Additionally, TiO₂has the drawbacks of the high recombinationrate of the photo electron-holes, which greatly restricts its applications. Recently, inorder to improve its photocatalysis efficiency and the utilization of sunlight, manyresearchers have been developed some methods to solve these problems, such as noblemetal deposition, ion doping and combination with semiconductors.TiO₂nanotube （TiO₂NT） arrays prepared by anodization has attracted extensiveinterests, because of its simple preparation process, and TiO₂NT prepared has theadvantages of uniform structure, high orientation, large surface area, chemical stability,and recycle. In this work, with the remove of organic pollutants and detecting theglucose effectively as goals, we studied the application of TiO₂NT modified withsemiconductor in the field of photo-catalytic degradation of organic pollutants andsensor. Specific contents are as follows:（1） Preparation, characterization and photo catalytic properties of SnO₂/TiO₂nanotube arrays （SnO₂/TiO₂NT） composite materials: TiO₂NT modified with SnO₂nanoparticles were prepared by a pulsed electrodepositon technique. Homogeneous SnO₂nanoparticles deposited on the surface of TiO₂NT were obtained. The results showedthat the photoelectric current density of the SnO₂/TiO₂NT was more than twice that ofbare TiO₂NT. Among these samples of TiO₂NT modified with SnO₂nanoparticles,120-SnO₂/TiO₂NT had the highest photocatalytic degradation efficiency, and acidorange7（AO7） was degraded completly after^-150minutes illumination.（2） Preparation, characterization and photo catalytic properties of In₂S₃/TiO₂nanotube arrays （In₂S₃/TiO₂NT） composite materials: In₂S₃nanoparticles werefabricated via a simple successive ionic layer adsorption and reaction method to thesurface of TiO₂NT, and tested as photocatalysts for degradation of^-2,4-dichlorophenoxyacetic acid （2,4-D）. Compared with the bare TiO₂NT, In₂S₃/TiO₂NTshowed stronger absorption in the visible light region and significantly enhanced thedensity of the photocurrent. The degradation efficiency of initial concentration of^-20mg/L^-2,4-D reached95.8%by using In₂S₃/TiO₂NT as photocatalyst within3h, while the removal efficiency was only56.1%by using the bare TiO₂NT.（3） Preparation, characterization and application in the field of sensor of CuO/TiO₂nanotube arrays（CuO/TiO₂NT） composite materials: CuO/TiO₂NT composite wasfabricated by a simple seed-mediated synthesis method. Cu nanoparticles were firstlyelectrodeposited onto the TiO₂NT arrays, and then oxidized to CuO nanofibers in theoxidizing solution, CuO/TiO₂NT was obtained by annealing in air. CuO/TiO₂NTelectrode was developed as nonenzymatic sensor for electrocatalytic detection of glucose.The results showed that the linear range of detection of glucose extended up to^-2.0mM(R=0.997, n=^-10). The sensitivity was79.79μA cm^-2mM^-1, and the detection limitwas^-1 μM （S/N=3）. Significantly, CuO/TiO₂NT electrode showed excellentanti-interference ability and stability. The sensor was also used to detect glucose inhuman blood serum samples.