Efficient synthesis of sunlight-driven ZnO-based heterogeneous photocatalysts

A series of ZnO-based heterogeneous photocatalysts, including Ag-ZnO, ZnO- and Ag-ZnO-reduced graphene oxide (rGO) nanocomposites, was successfully synthesized by a one-pot solvothermal route. The as synthesized products were systematically characterized using combined techniques of X-ray diffraction, X-ray photoelectron spectrometry, electron microscopy, and energy dispersive spectrometry. The resulting ZnO-based photocatalysts exhibited selective photocatalytic behavior towards the degradation of different organic dyes under solar light irradiation. Compared with plain ZnO nanoparticles, the heterogeneous nanocomposite photocatalysts of Ag-ZnO, ZnO- and Ag-ZnO-rGO showed significantly improved photocatalytic activities. The Ag-ZnO nanocomposite exhibited the highest photocatalytic efficiency, which can be ascribed to its core-shell structure with strong interfacial coupling between the Ag shell and the ZnO core as well as the surface plasmon resonance effect of the Ag. The ZnO- and Ag-ZnO-rGO nanocomposites displayed excellent recyclability, due to the strongly coupled interactions between the ZnO or Ag nanoparticles and the rGO support. The ZnO-rGO nano composite is the most promising candidate for photocatalysis application with excellent comprehensive performance. This study will not only provide guidance for the selection of ZnO-based heterogeneous photocatalysts, but also open new opportunities for the synthesis of other heterogeneous photocatalysts. (C) 2016 Elsevier Ltd. All rights reserved.