Synthesis and photocatalytic application of Au/Ag nanoparticle-sensitized ZnO films

Here it is demonstrated that the Au–Ag-ZnO architecture can be immobilized on indium tin oxide (ITO) substrate through a facile three-step synthesis approach. A series of ZnO films with different modifications of Au and Ag were applied to study the effect of Ag and Au nanoparticles on the morphology, optical properties and photocatalytic activity. An annealing treatment of the ZnO nanosheets before Ag–Au deposition is found to play an important role in the properties of the Au–Ag-deposited ZnO nanosheet (Au–Ag-ZnO). The annealing treatment results in a significant increase in the surface area of ZnO, and consequently an increase in the depositing amount of Ag nanoparticles. The Au–Ag-ZnO film shows nearly twice the photocatalytic efficiency than pure ZnO, and much higher efficiency comparing with the Ag-ZnO film in the photocatalytic degradation of methyl orange (MO) under UV illumination in aqueous solutions.