Synergic effect of the TiO2-CeO2 nanoconjugate system on the band-gap for visible light photocatalysis

The TiO2-CeO2 photocatalytic system in films is proposed here, in order to obtain photocatalytic systems that can be excited by solar light. The films were obtained through the electrophoretic deposition (EPD) of TiO2-CeO2 gel on sputtered Ti Corning glass substrates. The synergic effect of CeO2 in TiO2 films was analyzed as a function of the optical band gap reduction at different concentrations (1, 5, 10, and 15 mol%). The effect of two thermal treatments was also evaluated. The lowest band gap value was obtained for the sample with 5 mol% ceria that was thermally treated at 700 °C. The nanostructured films were characterized by Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high angle annular dark field (HAADF), high resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM). The nanocomposites were formed by TiO2 and CeO2 nanoparticles in the anatase and fluorite type phases, respectively.