The Biomimetic Synthesis, Characterization And Properties Of Polyoxometalates Materials

Polyoxometalates (POMs) constitute a large class of inorganic compounds with considerably potential applications in catalysis, and material sciences. Since polyoxometalates (POMs) have been synthesized, they have been gradually applied in many fields and attracted more attention due to their fascination variety of architectures. The microporous structure decides different properties of materials, such as delivery behavior, catalytic activity, separating efficiency, adherence, storage and released kinetics, etc. The purpose of our work is promoted by improving the properties of the materials (modifing the surface of material and introducing the special microporous structure, such as hollowness and micropore). In our work, we have synthesis POMs composites materials with high BET surface areas, core-shell structure and high catalytic activity.Polyoxometalates have both acidity and redox properties. In this article, POMs / SiO₂ composite materials with core-shell structure have been synthesized by sol-gel technology, biomimetic synthesis and biological template method. We have characterized the POMs composites materials by elements analysis, IR, XRD, UV, SEM and TEM. The results is listed as follows:1. Usingγ- K8SiW₁₀O36 as precursor and combined with SiO₂, we have prepared SiW₁₀ / SiO₂ composite materials with core-shell structure by sol-gel technology and biological template approach. The composite materials SiW₁₀ / SiO₂ still remained Keggin structure.2. Using H₃PW₁₂O₄₀ as precursor and combined with SiO₂, we have prepared PW12 / SiO₂ composite materials with core-shell structure by sol-gel technology and biological template approach. The composite materials [γ-SiW₁₀O₃₆] / SiO₂ still remained Keggin structure.3. Using H₃PMo₁₂O₄₀ as precursor and combined with SiO₂, we have prepared PMo₁₂ / SiO₂ composite materials with core-shell structure by sol-gel technology and biological template approach. The composite materials PMo₁₂ / SiO₂ still remained Keggin structure.The IR spectra showed that the three POMs composite materials still remained Keggin structure, chemical interactions were existed between POM molecules and silica for the microporous POM composites. All the diffraction peaks of the XRD could be readily indexed to criterion. These results indicate that the heteropolyanion in the asprepared composite materials retain original Keggin structure.The morphology and microstructure of the prepared POMs composite materials are investigated by the scanning electron microscopy (SEM). The surface of POMs composite materials is microporous structure, and the hollow structure is formed by calcination. In order to research the catalytic activity of the POMs composite materials, we designed a reaction of degradation of dye (safranine T). The result shows that the POMs composite...