Photocatalytic antibacterial effectiveness of Cu-doped TiO₂ thin film prepared via the peroxo sol-gel method

Cu-doped titanium dioxide thin films (Cu/TiO₂) were prepared on glass substrate via peroxo sol-gel method and dip-coating process with no subsequent calcination process for the degradation of organic dye and use as an antibacterial agent. The as-prepared materials were characterised using transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). For photocatalytic degradation of methylene blue in water, the samples were subjected to Ultraviolet C (UVC) and visible light irradiation. Degraded methylene blue concentration was measured using UV-Vis spectrophotometer. The antibacterial activities of the samples were tested against the gram-negative bacteria Escherichia coli (ATCC25922). Copper species were present in the form of CuO on the surface of modified TiO₂ particles, which was confirmed using TEM and XPS. The optimal observed Cu/TiO₂ weight ratio of 0.5 represents the highest photocatalytic activities under both UVC and visible light irradiation. Moreover, the same composition remarkably exhibited high antibacterial effectiveness against E. coli after illumination with ultraviolet A. The presence of CuO on TiO₂ significantly enhanced photocatalytic activities. Therefore, active Cu-doped TiO₂ can be used as a multipurpose coating material.