Visible light assisted photocatalytic degradation of acid red 88 using Au–ZnO nanophotocatalysts

Photocatalytic degradation of acid red 88 (AR88) in aqueous suspensions of Au–ZnO nanoparticles under visible light illumination was studied in order to evaluate various effects of the Au deposition on the ZnO photocatalytic activity. Au–ZnO nanoparticles were prepared by deposition precipitation method and characterized by different analytical techniques. In Au–ZnO system, all gold nanoparticles were tethered on the surface of zinc oxide particles. This enhanced the AR88 adsorption on the Au–ZnO surface and acted as electron traps which is the main reason for significant enhancement in the AR88 photodegradation under visible light illumination compared to ZnO alone. Further in the presence of electron acceptors complete decolorization of the dye was observed, which might be due to immediate trapping of the photogenerated electrons by electron acceptors.