Bactericidal performance of visible-light responsive titania photocatalyst with silver nanostructures

Titania dioxide (TiO(2)) photocatalyst is primarily induced by ultraviolet light irradiation. Visible-light responsive anion-doped TiO(2) photocatalysts contain higher quantum efficiency under sunlight and can be used safely in indoor settings without exposing to biohazardous ultraviolet light. The antibacterial efficiency, however, remains to be further improved.

Using thermal reduction method, here we synthesized silver-nanostructures coated TiO(2) thin films that contain a high visible-light responsive antibacterial property. Among our tested titania substrates including TiO(2), carbon-doped TiO(2) [TiO(2) (C)] and nitrogen-doped TiO(2) [TiO(2) (N)], TiO(2) (N) showed the best performance after silver coating. The synergistic antibacterial effect results approximately 5 log reductions of surviving bacteria of Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Acinetobacter baumannii. Scanning electron microscope analysis indicated that crystalline silver formed unique wire-like nanostructures on TiO(2) (N) substrates, while formed relatively straight and thicker rod-shaped precipitates on the other two titania materials.

Our results suggested that proper forms of silver on various titania materials could further influence the bactericidal property.