Self-assembly synthesis of CuO/ZnO hollow microspheres and their photocatalytic performance under natural sunlight

The ZnO nanostructure is difficult to apply in sewage treatment because of its low photocatalytic efficiency, narrow spectrum response, high photogenerated carrier recombination rate, and difficult retrieval from aqueous solution. CuO coupling could improve both the absorption of visible light and photocatalytic performance of ZnO nanoparticles. In this paper, the ZnO/CuO hollow microspheres was fabricated by a self-assembly method without a template. The experimental results showed that ZnO/CuO hollow microspheres (4 mu m) were successfully prepared via the hydrothermal method. CuO coupling greatly ameliorated the photocatalytic performance of ZnO microspheres under natural solar light or visible light, and the photodegrading rate in natural solar light was approximately 6 times greater than that of pure ZnO spheres. In addition, ZnO/CuO spheres showed good photocatalytic stability. The enhanced catalytic activity is associated with the reduced impedance of the ZnO sphere via CuO coupling, which promotes the separation of e(-)/h(+) carriers and enlarges the spectrum response to visible light.