氧化钼-二氧化钛复合膜的可见光致变色性能研究

采用溶胶凝胶法制备了一系列氧化钼-二氧化钛纳米复合物, 用柠檬酸作分散剂, 将得到的纳米复合物粉末分散成溶胶, 涂膜制备了具有可见光变色性能的均匀透明的光致变色(λ≥420 nm)复合膜. 通过红外、XPS、ESR测定表明, 在氧化钼、二氧化钛复合界面上生成了Mo—O—Ti键, 此键的存在是该复合膜具有可见光致变色响应的内在原因. 在可见光的照射下, 电子从二氧化钛的价带经由Mo—O—Ti键, 被激发到氧化钼的导带上. 研究了光致变色过程的动力学, 发现光致变色反应的速率取决于膜中复合物的摩尔比(MoO₃]/TiO₂])以及电荷转移能量(CTE).

Study on the Visible Light Photochromism of Molybdenum Oxide-Titania Composite Films

MoO₃•H₂O-TiO₂ composites with different molar ratios of MoO₃/TiO₂ (2～10) prepared by sol-gel method were deposited into thin films by using citric acid as dispersant. The thin films prepared show visible light photochromism (λ≥420 nm). It was identified that the Mo—O—Ti bond formed at the interface of MoO₃•H₂O and TiO₂ in the composites facilitated the charge transfer from TiO₂ to MoO₃•H₂O and was responsible for the visible light photochromism of the composite films. The kinetics of the coloration process of the composite film was also investigated to find that the rate of the coloration process strongly depended on the charge transfer energies and molar ratios of MoO₃/TiO₂ in the films.