Surface plasmon quenched of near band edge emission and enhanced visible photocatalytic activity of Au@ZnO core-shell nanostructure

Abstract

In this research work, we have demonstrated the synthesis of Au@ZnO core–shell nanostructure by a simple two-step chemical method. The ZnO coating enhance the charge separation process, whereas higher shell thickness suppresses the surface plasmon resonance (SPR) absorption of Au core and quenches the near band edge emission of ZnO. The photocatalytic activity of Au@ZnO nanostructure is evaluated by the degradation of methyl orange (MO) dye and oxidation of methanol under visible irradiation. Compared to pure ZnO nanoparticles (NPs), Au@ZnO core-shell NPs exhibit efficient plasmonic photocatalytic activity because of the presence of SPR in the Au core. The photocatalytic activity of the Au@ZnO core-shell NPs is enhanced by the shell thickness. Moreover, a possible mechanism for the photocatalytic activity of Au@ZnO under visible light irradiation is also proposed.