High efficiency self-cleaning of nanocomposites ZnO with additional chitosan for helping electron and hole transport

ZnO/chitosan coated wool fabric has been applied as a self-cleaning which obtained through sol-gel method for various pH: 5, 7, and 9. The self-cleaning test was carried out by irradiating the cloth samples using UVA-UVB lamps up to 15 h with dye for the clothing stain. ZnO/chitosan composites were characterized using X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), and UV–Visible spectroscopy. The diffraction spectra from chitosan for pH 9 is 19.56◦. The vibration bond at the wavenumbers 422 cm− 1 - 621 cm− 1 identified as Zn–O bond and at the wavenumber 3495 cm− 1 identified for stretching -OH and -NH2 from chitosan. Optical properties were analysed using the Kamers Kronig (K–K) relation which was applied to the FTIR spectra and shows the highest distance between two optical photon vibration modes (Δ (LO-TO)) is 199 cm− 1 was obtained when the pH 9. The pH 9 is the best self-cleaning performance for dye stain which completely lost after being exposed for 15 h irradiation. Samples pH 9 shows the best self-cleaning due to the smallest crystallite size and highest bandgap and (Δ (LO-TO)) indicated high potential for new self-cleaning material in future.