Physical and photocatalytic properties of zinc ferrite doped titania under visible light irradiation

Visible light responsive zinc ferrite doped titania photocatalyst (TiO2(ZnFe2O4)) was prepared by sol-gel method and was calcined at different temperatures. Diffuse reflectance spectroscopy (DRS) results show that the absorption edge of TiO2(ZnFe2O4) has moved to the visible spectrum range in comparison with the undoped titania. The photocatalytic experimental result demonstrates that TiO2(ZnFe2O4) powder can effectively photodegrade methyl orange (MO) under visible light irradiation. Effect of calcination temperature on the photocatalytic activity of TiO2(ZnFe2O4) was also investigated. Zeta potential measurements indicate that the isoelectric point (IEP) of the TiO2(ZnFe2O4) powder shifts to lower pH units with the increase of calcination temperature. Brunauer-Emmett-Teller (BET) surface area decreases with the rise of calcination temperature. It is concluded that the surface charge and BET surface area are the key factors for the higher photoactivity of zinc ferrite doped titania photocatalyst calcined at 400 degreesC. (C) 2004 Elsevier B.V. All rights reserved.