A novel photochemical technique for preparing silver doped titanium dioxide powder and coating for bactericidal applications
With the onset of multi-drug resistance in many bacterial strains, new bacteria-killing methodologies are increasingly being sought. Silver (Ag) nanoparticles, in particular, have received much interest because of their powerful anti-bacterial and anti-viral properties, even at low concentrations. Another recent development in this area is titanium dioxide (TiO2) powder and thin film coatings which have a photo-sterilisation effect upon UV excitation. This project seeks to enhance the bacterial killing effect of visible light active TiO2 by depositing ultrafine silver nanoparticles onto its surface using a novel low energy technique. The careful coupling of a metal (silver) and a carrier oxide (TiO2) created using this technique, with the pertinent combination of visible light activity, is expected to give rise to improved bactericidal activity.
Major achievements and highlights
X-ray Photoelectron Spectroscopy showed that the Ag species exist as Ag0 and Ag+ on the surface of the TiO2 nanoparticles. The presence of Ag0 was further confirmed by a plasmon peak at 490-530 nm in UV-Visible Reflectance Spectroscopy measurement. The Ag doped TiO2 showed enhanced photocatalytic activity and killing of E. coli due to the ability of Ag to trap electrons and to disrupt cell functions.
Future plans and directions
Future work will focus on the durability and reusability of the silver deposition and TiO2 coating. The application of the coatings will be extended to infectious diseases and food-borne pathogens.
