Co^(2+)掺杂的纳米TiO_2薄膜光催化特性及电化学阻抗谱研究

The Photocatalytic Properties and Electrochemical Impedance Spectroscopy of Co^(2+) Doped TiO_2 Thin Film

本文采用交流电沉积技术,在多孔氧化铝模板中合成出Co2+掺杂的纳米TiO2薄膜(Co2+/TiO2薄膜)。以次甲基蓝为降解物,研究了纳米Co2+/TiO2薄膜在可见光下的催化性能,考察了阳极偏压对光催化活性的影响。用电化学阻抗谱(EIS)研究了纳米Co2+/TiO2薄膜在次甲基蓝溶液中的电化学行为,给出了相应的等效电路和半导体能带结构参数-空间电荷层宽度。研究表明,适量Co2+掺杂可以提高TiO2薄膜的光催化活性。在Co2+/TiO2膜电极上施加一定阳极偏压,使空间电荷层宽度增加,因此能有效实现光生电子-空穴分离,进一步提高次甲基蓝的光催化降解效率。

The Co^2＋ doped nano-TiO2 thin film （Co^2＋/TiO2 thin film） was prepared by the A.C. electrodeposition method into porous alumina temple. The photocatalytic property of the nano-Co^2＋/TiO2 thin film was evaluated by degradation of methylene blue under visible light irradiation, and the effect of anode bias on photocatalytic activity was investigated. The electrochemical behavior of nano-Co^2＋/TiO2 thin film was investigated by means of Electrochemical Impedance Spectra （EIS） in methylene blue solutions, relevant equivalent circuit and the band structure parameter-the width of space charge layer were also presented . The results show that Co^2＋ doping can improve the photocatalytic activity of nano-TiO2 thin film.When an anode bias was applied on the nano-Co^2＋/TiO2 thin film, the width of space charge layer increased than without the bias, suggesting more efficient separation of photogenerated electron-hole pairs, the degradation efficiency of methylene blue can be greatly increased.