Bi2WO6 photocatalytic films fabricated by layer-by-layer technique from Bi2WO6 nanoplates and its spectral selectivity

Bi2WO6 multilayer films have been fabricated successfully by a layer-by-layer (LbL) technique from Bi2WO6 nanoplates, which show higher visible-light photoactivity (λ>420 nm) than that of Bi2WO6 nanoplate powders and P25 TiO2 films. The films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV–visible absorption spectroscopy. Photocatalytic activities of the films were evaluated by the rhodamine B (RhB) decomposition under UV and visible-light irradiation. Thickness and photoactivity of the film can be modified easily by changing the deposition cycles. Bi2WO6 films have the spectral selectivity of the photocatalytic degradation of RhB. Under the wavelength greater than 300 nm, the RhB molecules tend to be transformed to rhodamine over Bi2WO6 films selectively. However, in the case of shorter wavelength (λ=254 nm) light irradiation, the RhB molecules can be photodegraded completely.