Photocatalytic self-cleaning properties of lanthanum and silver co-doped TiO2 nanocomposite on polymeric fibers

Titania, single-doped and lanthanum-silver co-doped titania nanocomposite were coated on cellulosic and polyacrylonitrile fibers via sol-gel method. The prepared samples were evaluated using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and BET surface area measurement. The photo self-cleaning activity of the nanocomposites coated-fibers were determined by degradation of methylene blue and eosin yellowish under UV-Vis light. Diffuse reflectance spectroscopy was used to monitor photodegradation of dyes. The results of EDX and XPS revealed that La and Ag was doped into TiO2 structure. The results of EDX, TEM and BET analyses indicated that the TiO2 and TiO2 nanocomposite coatings were composed of nanoparticles or aggregates with a size of less than 20 nm. All samples demonstrated photocatalytic self-cleaning properties when exposed to UV-Vis irradiation. The results showed that the La3+/Ag+ co-doping is more beneficial than single doping of TiO2 coating and the synergistic effect of La3+ and Ag+ is responsible for improving the photo-activity. This may be ascribed to the microstructure of TiO2 and the effect of the doping modes on the structural and electronic properties of the anatase phase.