Photocatalytic generation of silver nanoparticles and application to the antibacterial functionalization of textile fabrics

An all-inorganic protocol, entirely based on wet chemistry methods, has been studied to form nano-sized Ag metallic particles in solution. Liquid suspensions of anatase TiO2 nanocrystallites have first been prepared through a sol–gel route. Silver nanoparticles (NPs) have then been generated through the photocatalytic reduction of a silver salt, diluted in TiO2 liquid suspensions, and exposed to UV light, which results in the formation of a mixed Ag–TiO2 suspension. Mechanisms occurring in solutions during the metallization step and a post-metallization ageing period have been studied by UV/vis spectroscopy. Chemico-structural and morphological properties of resulting silver NPs have been studied by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Ag–TiO2 suspensions have then been impregnated on cotton-based textile samples and the antibacterial activity of so-functionalized textiles has been studied with respect to E. coli and L. innocua bacteria. It is shown that, while TiO2 NPs attached to textile fibres have no antibacterial activity, functionalized textiles exhibit a strong antibacterial activity due to Ag NPs, and this activity can be reached for a large range of impregnated silver amounts.