One-step preparation of nitrogen doped titanium oxide/Au/reduced graphene oxide composite thin films for photocatalytic applications

Titanium dioxide (TiO2) and TiO2/Au/reduced graphene oxide (rGO) nanocomposite thin films were grown by ultraviolet matrix assisted pulsed laser evaporation (UV-MAPLE) in controlled O-2 or N-2 atmospheres. An UV KrF* excimer laser (lambda = 248 nm, tau(FWHM) similar to 25 ns, nu = 10 Hz) was used for the irradiation of the MAPLE targets consisting of TiO2 nanoparticles (NPs) or mixtures of TiO2 NPs, Au NPs, and graphene oxide (GO) platelets in aqueous solutions. The effect of Au and GO addition as well as nitrogen doping on the photocatalytic activity of the TiO2 thin films was investigated. The evaluation of the photocatalytic activity was performed by photodegradation of the organic methylene blue model dye pollutant under UV-visible light, simulated sun irradiation conditions. Our results show that the photocatalytic properties of TiO2 were significantly improved by the addition of Au NPs and rGO platelets. Nitrogen inclusion into the rGO structure further contributes to the enhancement of the TiO2/Au/rGO nanocomposites photocatalytic activity.