Efficient visible light-induced photocatalytic degradation of methyl orange by QDs sensitized CdS-Bi2WO6

Photocatalytic active Bi2WO6 sensitized by CdS quantum dots (QDs) was synthesized via a chemical hydrothermal approach for the first time. The QDs sensitized CdS-Bi2WO6 photocatalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy (UV-vis) and photoluminescence spectra (PL). The photocatalytic activities of QDs sensitized CdS-Bi2WO6 samples were investigated based on the decomposition of methyl orange and phenol in aqueous solution under visible light irradiation (lambda > 420 nm). The DRS results revealed that CdS-Bi2WO6 samples have a red shift and stronger absorption in the visible light region. After being sensitized by CdS QDs, the Bi2WO6 samples showed the high efficiency for the degradation of methyl orange. The enhanced photocatalytic performance could be attributed to the synergic effect between CdS QDs and Bi2WO6, which promoted the migration efficiency of photo-generated carriers. According to experimental results, the possible photocatalytic mechanism of the CdS-Bi2WO6 photocatalyst was proposed in order to guide the further improvement of its photocatalytic activity. (C) 2011 Elsevier B.V. All rights reserved.