In this study, different samples of doped TiO2 nanoparticles (5 mol% Cu, 5 mol% Si, 5 mol% Zr) were prepared via simple sol−gel synthesis method by using Zirconyl nitrate hydrate as Zr precursor, Tetra ethoxysilane as Si precursor, Copper nitrate trihydrate as Cu precursor and titanium (IV) butoxide (TBT) as titanium precursor. The effects of doping on the structural, optical, and photo-catalytic properties of nanoparticles were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), TEM and UV-Vis absorption spectroscopy. The XRD showed that the presence of only anatase TiO2 for the undoped and doped titania samples. The prepared doped TiO2 photocatalyst nanoparticles showed optical absorption edge in the visible light region and exhibited excellent photo-catalytic ability for degradation of methyl orange (MO) solution under visible irradiation. Visible photo-catalytic activity of doped TiO2 samples was obviously higher than that of pure TiO2 and reached the maximum at Cu, Si and Zr contents of 5 mol%, 5 mol% and 5 mol% (TCSZ sample), based on MO dye decomposition rate.
