Silver and gold modified plasmonic TiO2 hybrid films for photocatalytic decomposition of ethanol under visible light

Plasmonic noble metal nanoparticles (NPs) (silver and gold) are able to sensitise photocatalysts in visible light by modifying the TiO2 surface with 0.5 wt% loading. These plasmonic catalysts were supported by optically transparent zirconium dioxide and layer silicate. The hybrid catalyst films (with ∼10 μm thickness) were prepared by sputtering the aquatic suspension of the catalyst/support suspension on glass slides and irradiated the films by visible light (λ ≥ 435 nm). The photocatalytic efficiency was studied on decomposition of ethanol vapour, and the residual concentration of ethanol was monitored. The intermediates during illumination were analysed by GC–MS. Modifications with silver and gold lead to a change in the optical properties due to the plasmonic light absorption on TiO2. The supporting binding materials are almost transparent in UV–vis wavelength range, thus Ag- and Au-modified TiO2 can be excited by the incoming light without much loss of the photon energy. Furthermore, the layered silicate promoted the photocatalytic process by its high adsorption capacity. Due to these two phenomena, a synergistic effect was found on the photocatalytic activity of the nanocomposite hybrid films.