Enhanced photocatalytic bacterial inactivation of atomic-layer deposited anatase-TiO thin films on rutile-TiO nanotubes.

In this work, experimental conditions were established to fabricate self-ordered rutile-TiO nanotube arrays, coated with a conformal anatase-TiO thin layer using atomic layer deposition. E. coli inactivation tests showed a considerable increase in photocatalytic activity using rutile-TiO nanotubes coated with anatase-TiO compared to that using single rutile or anatase TiO nanotubes only. Photocatalytic hydroxyl radical generation rates (determined by pNDA bleaching) were also meaningfully enhanced for the combined anatase/rutile TiO nanostructures. Therefore, we show that it is possible to take advantage of the morphological properties of the materials and the synergic effect from the combination of both TiO polymorphs during the design of novel materials, which could be used as antibacterial agents to improve the quality of drinking water.