M.A Behnajady - Department of Applied Chemistry, Islamic Azad University, Tabriz Branch, P.O.Box ۱۶۵۵, Tabriz
L asharnejad
n modirshahla
m shokri

In recent years, many studies have been focused on the photocatalytic degradation of organic compounds mediated by semiconductor particles, such as TiO2 and ZnO, acting as photocatalysts. Previous studies have proved that such semiconductors can degrade most kinds of persistent organic pollutants under ultraviolet (UV) light irradiation[1,2]. A photocatalytic process is based on the generation of electron-hole pairs by means of band-gap radiation that can give rise to redox reaction with the species adsorbed on the surface of photocatalysts. However, the fast recombination rate of the photogenerated electron/hole pairs hinders the commercialization of this technology. Various attempts have been made to reduce e- - h + recombination in photocatalytic processes. Coupled semiconductor photocatalysts may increase the photocatalytic efficiencyby increasing the charge separation and extending the photo-responding range[3]. The objective of the present study is to optimize the preparation for the coupled ZnO/SnO2 nanoparticles. For this purpose, a series of nanosized coupled ZnO/SnO2 photocatalysts with different Sn contents were prepared and their photocatalytic activities evaluated using C.I. Acid Red 27 (AR27) as a model organic contaminant