Effect of doping mode on the photocatalytic activities of Mo/TiO 2

Abstract

The thin films of photocatalyst, TiO 2 doped by Mo 6+ in different forms, were prepared by sol–gel method. The photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis transmittance spectra and electrochemical impedance spectroscopy, and the photocatalytic activity was characterized by photocatalytic degradation of aqueous methyl orange under UV radiation. The results showed that the TiO 2 doped by Mo 6+ extend absorption edge and interfacial charge transfer resistance decrease. The photocatalytic activity of TiO 2 doped by Mo 6+ in bottom is much better than that of pure TiO 2, those doped in surface, or those doped uniformly. The activity of TiO 2 doped by Mo 6+ in bottom mode at optimal concentration, 1 at.%, increased nearly two times than pure TiO 2. The effects of doping modes on the photocatalytic activities were discussed in the terms of separateness of charge carriers that there maybe form barrier of carrier in bottom doping mode and then restraining the (e −–h +) pair recombination.