TiO2 thin films non-uniformly doped by La 3+ were prepared by sol-gel method. The comparison of thin film activities, which was characterized by photocatalytic degradation of methyl orange, shows that doping modes have great effects on photocatalytic activities. The non-uniformly doped TiO2 films result in good photocatalytic activities with an optimal concentration; about 0.5%（atom fraction）. UV-Vis transmittance spectra indicate that the absorption edges of these TiO2 thin films shift to ward longer wavelengths remarkably, and electrochemical behavior also reveales that e--h+ pairs are prone to formation and separation under UV irradiation. The mechanism of photocatalytic activities are enhanced by La 3+ non-uniformly doping was discussed on the analogy of the theory of “window effect” of solar cell heterojunction.
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