A new visible-light photocatalyst: CdS quantum dots embedded mesoporous TiO2.

Cadmium sulfide quantum dots (QDs) sensitized mesoporous TiO2 photocatalysts were prepared by preplanting cadmium oxide as crystal seeds into the framework of ordered mesoporous titanium dioxide and then converting CdO to CdS QDs through ion-exchange. The presence of CdS QDs in the TiO2 framework extended its photoresponse to the visible-light region by accelerating the photogenerated electron transfer from the inorganic sensitizer to TiO2. The new photocatalyst showed excellent photocatalytic efficiency for both oxidation of NO gas in air and degradation of organic compounds in aqueous solution under visible light irradiation. The photocatalysts were characterized byX RD, N2 adsorption-desorption, TEM, XPS, UV/vis, and PL spectroscopy. The relationship between the physicochemical properties and the photocatalytic performance of the sample is discussed.