The influence of alizarin and fluorescein on the photoactivity of Ni,Pt and Ru-doped TiO2 layers

The doping with different metal ions and sensitization with organic compounds are two well known methods used to improve the photoactivity of TiO₂. In this respect, the metallic ions-doped TiO₂ samples were prepared by embedding Ni, Pt and Ru ions into TiO₂ crystalline network and then, each sample was sensitized with alizarin and fluorescein dyes. The qualitative evaluation of prepared TiO₂-based materials was made by: UV–vis spectroscopy, spectrofluorimetry, FT/IR spectroscopy and microscopy, X-ray diffraction and N₂ physisorption measurements. The optoelectronic properties investigated by UV–vis spectroscopy show that the optical response of Ni-doped TiO₂ layer shifts to visible. The X-ray spectra do not show peaks of nickel, platinum and ruthenium oxide crystals or pure metals. The FT/IR spectra proved the presence of dye molecules adsorbed on titania nanoparticles surface. These results demonstrated that the studied dopants and dyes have potential to promote modified TiO₂-based materials as good candidates to be used in photolectrocatalytic processes.