Photocatalytic disinfection of water with Ag–TiO2 nanocrystalline composite
Abstract A method of solution impregnation and calcination has been demonstrated for synthesizing nanoparticles of Ag–TiO2 composite photocatalysts for use in the disinfection of water. Only a small proportion of the TiO2 surface is covered by nano-islands of Ag corresponding to a loading of 4 wt.% of Ag; thus, most of the TiO2 surface is available for photocatalytic function. Although the primary particles of both Ag and TiO2 are in the 10- to 20-nm range, microscopic studies indicate that the primary particles of Ag are deposited on nano-agglomerates of 30- to 70-nm-sized TiO2. It is seen that the relatively small loading of Ag has not caused any UV–vis spectral shift but has enhanced the rate of photocatalytic antibacterial action of TiO2, presumably by electron trapping.