The Preparation of a Novel Composite Film Based on Polyoxometalate for Visible Light Photocatalysis
The composite film, FeW11O399-(FeW11)/TiO2/ SiO2, was prepared by liquid phase deposition method (LPD) at low processing temperature for the first time. Formation of the stable composite film is due to strong chemical reaction of ≡Ti-OH from TiO2/SiO2 with the surface oxygen atoms at vacant sites of FeW11. The structural properties of the film were characterized using FT-IR、UV-vis spectra, Elemental Analysis. The experimental results confirmed the retention of the primary Keggin structure and the saturation of the surface of the lacunary FeW11; Formation of Ti–O–Si bond implies that the TiO2 crystallites highly dispersed on the silica surface via oxygen as a bridge. The catalytic activity was tested by the photo-degradation of aqueous azo dye congo red (CR) (0-20 mmol•L-1). The resulting film exhibited efficient visible-light photocatalytic activity to decompose aqueous azo dye CR，which is mainly attributed to long time existence of Fenton-assisted FeW11/TiO2/SiO2 excitation state. According to the experimental results, a synergistic effect mechanism of the photodegradation process is proposed.
Tianbiao Zhang and Jerry Tian
D. F. Li and Y. Liu, "The Preparation of a Novel Composite Film Based on Polyoxometalate for Visible Light Photocatalysis", Advanced Materials Research, Vol. 298, pp. 96-101, 2011