Preparation And Organic Dyestuff's Photocatalytic Degradation Properties Of Nanometer Polyoxometalates-Titania Composites

In this paper,A novel, simple, fast approach was developed for the synthesis of high-dispersed anatase nano-TiO₂ by a hydrothermal synthesis method. The powders are characterized by X-ray diffraction (XRD), transmission electron microscope (TEM). This catalyst was used for the photocatalytic degradation of Methyl Orange. The decomposition was further promoted by addition of H₂O₂, the variations of the H₂O₂ concentration effect were systematically investigated. An optimum concentration of hydrogen peroxide was observed at 12.5 mM.According to the method of document, I prepared the nanocomposites, H3PW12O40/TiO₂ (anatase),H4SiW12O40/TiO₂ (anatase). The structure of the composites was characterized by FT-IR. The H3PW12O40/TiO₂,H4SiW12O40/TiO₂ (anatase),TiO₂ photodegradation of Methyl Orange in aqueous solutions was investigated by using UV light. The effect of different catalysts, catalysts concentrations, the initial pH value and different inorganic anion were investigated. Results showed that the degradation of Methyl Orange could achieve 97% when the conditions of experiments were satisfied with catalyst H3PW12O40/TiO₂ was 1g/L, pH value is 3.5, the concentration of IO3- is 10-3M, radiation time was 90 min, and initial concentration of Methyl Orange was 30 mg/L.A series of the POM-containing composite films were prepared by a sol-gel method together with spin-coating and calcinations techniques. FT-IR indicates that the primary polyoxometalate structures remained. It was shown from the results that the strong chemical interaction between POM molecules and tatiana networks existed on the films. The photocatalytic activities of the POM/TiO₂ composite films were tested via the degradation of Sudanâ…¢. It was observed that the photocatalytic activities of the POM/TiO₂ composite films are much higher than that of the pure TiO₂ film, and the Fe3(PW9)2/TiO₂ composite films have the highest activity; This mainly attributed to the synergetic effect between POM and TiO₂.