Research upon Cu-Doping Contents in TiO 2 Nanoparticles Incorporated onto Cellulose Nanofibers for Dye Removal and Self-Cleaning Applications.

Cu-doping contents in the TiO 2 lattice structure were studied to show the effects on the crystal structure, morphology, and photocatalytic activity of TiO 2 nanoparticles and thus composite cellulosic nanofibrous membranes. Pristine and copper-doped TiO 2 nanoparticles were synthesized using the sol-gel technique, a wet chemical method with the advantages of low synthesizing temperature, uniform nanosize distribution, and purity. The as-synthesized semiconductor nanoparticles were first tested with the dye removal process and then impregnated onto electrospun cellulose nanofibers (CL nanofibers) to acquire modified nanofibers with self-cleaning properties. The as-prepared composite CL nanofibers consisting of doped and undoped TiO 2 nanoparticles were characterized by various techniques, such as field emission scanning electron microscopy, transmission electron microscopy, UV-vis, X-ray diffraction, Fourier transform infrared spectroscopy, and tensile tests. The copper-doped TiO 2 molar ratio in the nanocomposite was found to possess a pronounced impact on the dye removal and self-cleaning effects under the visible light spectrum, whereas TiO 2 is highly effective under specific UV-light irradiation. Optical measurements and dye decomposition showed that the Cu-doped TiO 2 nanocomposite was optimized at a 1% molar ratio by the copper-doping concentration regarding dye removal and self-cleaning applications under the visible light range.