The aim of this study was to investigate the effects of reaction temperature on the photocatalytic activity of TiO₂ with Pd and Cu cocatalysts. N₂ sorption, transmission electron microscopy and high-resolution transmission electron microscopy were used to characterize the specific surface area, pore volume, pore size, morphology and metal distribution of the catalysts. The photocatalytic destruction of methylene blue under UV light irradiation was used to test its activity. The concentration of methylene blue in water was determined by UV-vis spectrophotometer. Pd/TiO₂ catalyst was more active than Cu/TiO₂ and TiO₂. At 0–50 °C reaction temperature, the activity of TiO₂ and Pd/TiO₂ increased with an increase of reaction temperature. When the temperature was as high as 70 °C, the reaction rate of TiO₂ drop slightly and Pd/TiO₂ became less effective. In contrast, Cu/TiO₂ was more active at room temperature than the other temperatures. The results indicate that the photocatalytic activity of the catalyst is influenced by the reaction temperature and the type of cocatalyst. When the reaction temperature is higher than 70 °C, the recombination of charge carriers will increase. The temperature range of 50–80 °C is regarded as the ideal temperature for effective photolysis of organic matter. The effects of reaction temperature mainly influence quantum effect, i.e., electron-hole separation and recombination.

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.