Optical and photocatalytic properties of TiO2 films modified with oxides and gold

Films consisting of TiO2/ZrO2/SiO2 undoped and doped with Au nanoparticles were synthesized by the sol-gel method. The films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), spectroscopic ellipsometry (SE) and optical absorption (OA) methods. The XRD study demonstrates the formation of TiO2 anatase nanocrystals and Au nanoparticles. SE and OA measurements of the undoped films showed no significant absorption in the spectral range of 4001000 nm. Doping with Au nanoparticles resulted in the appearance of a surface plasmon resonance (SPR) absorption band at 600 nm as well as weaker absorption bands in the 300500 nm region. The observed changes in optical properties agreed with the enhanced photocatalytic activity of Au-doped TiO2/ZrO2/SiO2 films with gold compared to undoped films. The photocatalytic activity was evaluated by the photodegradation of the organic dye Rhodamine B. Under optimized conditions, the photodecomposition rate of the doped films was several times larger than that of the undoped films. Films of TiO2, TiO2/ZrO2/SiO2 and ternary oxides were investigated.