Enhanced photocatalytic bacterial inactivation of atomic-layer deposited anatase-TiO2 thin films on rutile-TiO2 nanotubes

Abstract

In this work, experimental conditions were established to fabricate self-ordered rutile-TiO₂ nanotube arrays, coated with a conformal anatase-TiO₂ thin layer using atomic layer deposition. E. coli inactivation tests showed a considerable increase in photocatalytic activity using rutile-TiO₂ nanotubes coated with anatase-TiO₂ compared to that using single rutile or anatase TiO₂ nanotubes only. Photocatalytic hydroxyl radical generation rates (determined by pNDA bleaching) were also meaningfully enhanced for the combined anatase/rutile TiO₂ 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 TiO₂ polymorphs during the design of novel materials, which could be used as antibacterial agents to improve the quality of drinking water.