Abstract
The antibacterial activity of sulfur-doped titanium dioxide (TiO2) thin film was investigated under visible-light illumination. Sulfur-doped TiO2 revealed visible-light-induced antibacterial activity against Escherichia coli that was higher than that of TiO2. The bactericidal activity increased further when various metals (e.g., copper, silver or nickel) were added to the sulfur-doped TiO2 as supplements. Most notably, the antibacterial activity of the sulfur-doped TiO2 was highest when supplemented with 4-7% copper. The antibacterial activity of the copper-supplemented sulfur-doped TiO2 was strong even under daily-used light conditions. Thus, following only 5 min exposure to visible light (1,700 lx), no viable cells were detected on the copper-supplemented sulfur-doped TiO2 coated surface that initially contained 106 CFU/mL E. coli. The utility of the copper-supplemented sulfur-doped TiO2 coating as an antibacterial agent was further confirmed by testing its effectiveness on the restroom floors of a nursing home. This antibacterial feature of the copper-supplemented sulfur-doped TiO2 makes it a suitable agent for applications in environmental decontamination.
