Direct Z-scheme of Cu2O/TiO2 enhanced self-cleaning, antibacterial activity, and UV protection of cotton fiber under sunlight

This work presents a modified solvothermal process for a facile synthesis of high thermally stable nanocrystalline anatase TiO₂ NPs doped with Cu₂O NPs. A Z-scheme mechanism was used to account for the enhanced photocatalytic activity exhibited by these materials. Also, the nanocomposite was impregnated in cotton fabric to obtain a modified fiber with high thermal stability, self-cleaning, enhanced UV protection, and antibacterial activity. The as-prepared nanomaterials and the coated fabric were characterized by various physicochemical techniques such as XRD, EDXRF, TGA, TEM, HRTEM, and SEM. The Cu₂O/TiO₂ molar ratio in the nanocomposite was found to possess a pronounced impact on the crystalline structure, size and morphology of TiO₂ NPs. The XRD revealed proper substitutions of the few Ti⁴⁺ sites by Cu²⁺ ions in TiO₂ host lattice. Optical measurements showed that the plasmonic peak of the Cu₂O/TiO₂ nanocomposite was affected by the copper-doping concentration, enhancing self-cleaning of Cu₂O/TiO₂ under direct sunlight. The TiO₂/fiber self-cleaning efficiency (12 h for MB removal) was increased by the in situ growing of Cu₂O (5.5 h). Antibacterial activity studies revealed high potential activity of Cu₂O/TiO₂ against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Kleissella pneumonia, Saccharomyces sp.) bacteria. The promising photocatalytic and biocidal activity of our synthesized Cu₂O/TiO₂ nanocomposites was ascribed to the reactive oxygen species generated by the Z-scheme mechanism under direct Sunlight.