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利用溶胶-凝胶法制备了磷钼酸/二氧化钛(PMoA/TiO2)复合薄膜.通过红外光谱(FT-IR)、原子力显微镜(AFM)和X射线晶体衍射(XRD)对复合薄膜的组成和结构进行了表征.利用紫外/可见吸收光谱(UV-vis)和电子自旋共振光谱(ESR)对复合膜的光致变色性能进行了研究.FT-IR分析结果表明,Keggin结构磷钼酸分子的基本结构在复合薄膜中仍然存在,在PMoA与TiO2界面间形成了Mo—O—Ti键电荷转移桥.AFM结果表明复合前后TiO2薄膜以及复合膜光照前后的表面形貌发生了显著变化.复合膜具有可逆的光致变色性质,在紫外光照下,复合薄膜由无色变为蓝色,蓝色薄膜在空气中暗处放置后可恢复为无色.ESR结果表明TiO2受紫外光激发产生光生电子,导致PMoA发生光还原反应,生成杂多蓝.PMoA/TiO2体系的光致变色过程是按照电子迁移的机制进行的.
The composite films of phosphomolybdic acid / titania (PMoA / TiO2) were prepared by sol-gel method. The composition and structure of the composite films were characterized by Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and X-ray diffraction (XRD) The photochromic properties of the composite films were investigated by UV-Vis and ESR.The results of FT-IR indicated that the Keggin structure of phosphomolybdic acid molecules The basic structure still exists in the composite film, and the Mo-O-Ti bond charge-transfer bridge is formed between the PMoA and the TiO2 interface.The AFM results show that the surface morphology of the TiO2 film and the composite film before and after light irradiation changes significantly. Reversible photochromic property, under the ultraviolet light, the composite film from colorless to blue, blue film placed in the dark after the air can be returned to colorless .ESR results show that the TiO2 by ultraviolet light generated photogenerated electron , Resulting in a photoreduction reaction of PMoA to generate heteropoly blue.The photochromism of PMoA / TiO2 system proceeded according to the mechanism of electron transfer.