Cr沉积TiO_2复合薄膜的制备及其可见光催化性能

真空蒸镀法结合溶胶凝胶法成功制备Cr沉积TiO2三层复合薄膜.通过XRD、SEM、UV-vis等手段表征沉积Cr后的TiO2薄膜的结构、可见光吸收性能,以亚甲基蓝溶液为目标物评定其可见光光催化活性.结果表明:该法制备的Cr沉积TiO2复合薄膜,在723 K热处理后,蒸镀的金属层仍然为金属Cr,823 K时被氧化为Cr2O3.不同温度热处理后Cr沉积的TiO2复合薄膜在可见光区均表现出良好的光吸收性.而且随着热处理温度的升高,光吸收性能明显增强.降解实验表明,823 K热处理后的薄膜样品光催化性能最好.在可见光光照射2 h后,对亚甲基蓝溶液降解率接近40%.

Preparation and Visiblelight Photo-catalytic Activity of Cr-doped TiO2 Composite Film

Cr-TiO2 composite films were prepared by a sol-gel and high vacuum evaporation method.The effects of Cr-doped on the microstructure,light absorption property,and photocatalytic activity of the samples were investigated.X-ray diffraction(XRD),scanning electron microscopy(SEM),and UV-vis absorption spectra(UV-vis) were used to characterize the obtained films.The photo-catalytic activity of as-prepared films was evaluated through the degradation of methylene blue.Results show that the plating layer of composite film exists as metallic Cr at 723 K and oxidized Cr2O3 at 823 K.The absorption edge shifted from an ultraviolet region for TiO2 to a visible light range for annealed Cr-doped TiO2 films.More and more Cr3+ diffuses into TiO2 thin film with increasing treated temperature,which leads to intense visible-light absorption.The degradation experiments show that the maximum visible-light catalytic activity is obtained at 823 K.The degradation of methylene blue is close to 40% under visible light irradiation for 2 h.