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

Abstract

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 O₂ or N₂ atmospheres. An UV KrF* excimer laser (λ = 248 nm, τ_FWHM ∼ 25 ns, ν = 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.