Photocatalytic properties of zeolite-based materials for the photoreduction of methyl orange

Novel photocatalytic materials have been prepared by incorporation of TiO2, a transition metal and, heteropolyacid (HPA) in the zeolite structure. These materials have been characterized using XRD, UV-vis diffuse reflectance spectroscopy and elemental analysis. The photocatalytic activity of the materials in visible light has been evaluated for photoreduction of methyl orange solution in the presence of a sacrificial electron donor 1:40 ethanol-water mixture. The material Zeo-Y/TiO2/Co2+/HPA photoreduces, methyl orange effectively to the extent of about 4.11 mg/g TiO2 and shows better photocatalytic activity as compared to Zeo-Y/TiO2/HPA, indicating the role of transition metal ions. The improved photocatalytic properties in the visible region could be due to the combined effect of transition metal ions and HPA, while these constituents along with the zeolite framework are also likely to contribute towards delay in charge recombination. (c) 2006 Elsevier B.V. All rights reserved.