Enhanced photocatalytic activity of Au-doped Au@ZnO core-shell flower-like nanocomposites

Abstract We introduce a simple and low-cost three-step hydrothermal and pulsed laser ablation technique for the fabrication of flower-like pure ZnO nanostructures, Au@ZnO core-shell nanocomposites, and Au@ZnO/Au core-shell nanocomposites doped with various concentrations (5, 10, and 15 wt%) of Au nanoparticles without using surfactants or catalysts to enhance the catalytic performance of ZnO under UV–visible irradiation. The decoration of Au nanoparticles on the surface of ZnO promoted the absorption of visible light due to the surface plasmon resonance of Au. Further, we evaluated the photocatalytic performance of the nanocomposites in the degradation of methylene blue (MB). Our findings revealed that the Au@ZnO/Au core-shell nanocomposites with 5 wt% of doped Au NPs demonstrated the highest photocatalytic activity. In addition, radical-scavenging experiments were conducted to determine the main reactive species formed in the reaction mixture, and accordingly, a plausible photocatalytic reaction mechanism for the enhanced photodegradation of MB is presented.