Photodegradation of rhodamine B under visible light by bimetal codoped TiO2 nanocrystals

In the search for efficient photocatalysts working under visible light, we have investigated the effect of metal ions (Bi/Co, Fe/Co) codoping on the photocatalytic activity of TiO2 prepared by stearic acid gel method. UV-vis spectra revealed that doped Co enhanced the absorbency of TiO2 under visible light, and Bi/Co codoped TiO2 showed higher absorbance than Fe/Co codoped TiO2. The photoreaction based on the prepared samples for photodegradation of 20 mg/l rhodamine B solution was examined. The results showed that Fe(0.1%)/Co(0.4%) codoped TiO2 had the highest photoactivity among all as-prepared samples under visible light, though less absorbency of visible light, indicating that the photoactivity not only benefits from absorbency but also relates to the cooperative effect of the two dopants.