Structure and Properties of Natural Dye-Sensitized Nano-TiO₂ Photocatalytic Self-Cleaning Cotton Fabrics

In this study the three natural dyes of madder, curcumin and gardenia blue were used as sensitizers to treat the nano-TiO2 which was prepared with the sol-gel method improved by plant honeysuckle extract, and then oxalic acid (OA) and citric acid (CA) were compounded as crosslinkers to modify the cotton fabric, The carboxyl groups on the modified cotton fabric can anchor the dye-sensitized nano-TiO2 to give it self-cleaning performance. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) showed that the dye-sensitized nano-TiO2 was successfully loaded on the surface of the cotton fabrics, and basically did not change their crystalline structure. UV-Visible diffuse reflectance spectra (UV-Vis-DRS) and Photoluminescence Spectroscopy (PL) spectra showed that, compared with nano-TiO2 photocatalytic cotton fabrics, the photocatalytic cotton fabric prepared from our dye-sensitized nano-TiO2 had a narrower band gap energy and a decrease in the recombination rate of electron-hole pairs. The cross-linked cotton fabric treated with dye-sensitized nano-TiO2 had excellent photocatalytic performance and washing resistance. In addition, the cross-linking treatment greatly improved the wrinkle recovery of the cotton fabrics, and the load of dye-sensitized nano-TiO2 endowed the fabric with excellent hydrophilic properties. but it also led to a certain degree of decrease in its breaking strength.