Preparation and characterization of Rb-doped TiO2 powders for photocatalytic applications

TiO2 nanoparticles doped with different concentrations of Rb were prepared by sol-gel method. The crystal structures of samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was confirmed by the Rietveld refinement method that the as-prepared samples crystallize in anatase phase and Rb doping induces expansion and distortion of the crystal lattice. Compared with the pure TiO2, the Rb-doped nanoparticles have smaller crystal size and better dispersibility. Degradation rate of methylene blue was used to evaluate the photocatalytic activity of Rb-TiO2. It indicated that doping Rb into TiO2 can effectively improve the photocatalytic activity of TiO2 and the mechanisms were discussed in detail. When using the sample doped with 0.20% Rb, methylene blue degraded with the fastest rate (97% within 60 min).