Structural and conductivity study of Y and Rb co-doped TiO2 synthesized by the sol–gel method

Nanoparticles of titanium dioxide co-doped with Y3+ and Rb+ were prepared using the sol–gel method and were characterized by thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. Y3+ and Rb+ co-doped TiO2 powder calcined at 800 °C shows a synergistic effect, which shifted the transformation anatase–rutile to higher temperature. X-ray diffraction and XPS analysis revealed that Y3+ and Rb+ did not enter into the crystal lattices of TiO2 and are uniformly dispersed onto TiO2 particles. In this study, the conductivity measurements were performed under ambient atmosphere on undoped and co-doped TiO2 in order to investigate the defect chemistry by identifying the predominant charge carriers. An increase in the conductivity σ of nano-TiO2 is shown when the samples were co-doped with Y3+ and Rb+.