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

Abstract

Titania, single-doped and lanthanum-silver co-doped titania nanocomposite were coated on cellulosic and polyacrylonitrile fibers <em>via</em> 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 TiO₂and the effect of the doping modes on the structural and electronic properties of the anatase phase.