Turbulent mixing of reactive fluids in sot-gel process allows elaboration of monodispersed pure, doped and composite TiO2 nanoparticles and nanocoatings on their base. In this work, we investigate the effect of hydroxyurea on the growth kinetic of TiO2 nanoparticules and photocatalytic activity of the prepared N-TiO2 nanocoatings in the visible. The materials was characterized by XRD, ATD, and XPS methods. Particular attention was given to their thermal treatment. Composite Ag(Au)-TiO2 nanocoatings were also prepared by surface reduction induced by the UV-A illumination of amorphous TiO2 nanoparticles.