Attachment of ZnO nanoparticles onto layered double hydroxides microspheres for high performance photocatalysis

In this study, ZnO nanoparticles were successfully deposited on the surface of ZnMgAl-CO3-LDHs microspheres to form ZnO/ZnMgAl-CO3-LDHs heterojunction photocatalysts by coprecipitation process. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-vis diffuse reflectance spectroscopy. The results show that ZnO nanoparticles with diameters about 10-80 nm are tightly grown on the nanosheets of the ZnMgAl-CO3-LDHs microspheres. Compared with the pristine ZnMgAl-CO3-LDHs microspheres and pure ZnO, the photocatalytic activity of the heterojunction ZnO/ZnMgAl-CO3-LDHs photocatalyst is significantly enhanced towards the degradation of phenol under UV light irradiation. The enhancement of the photocatalytic activity of the heterojunction catalysts can be ascribed to their improved light absorption property and the lower recombination rate of the photoexcited electrons and holes during the photocatalytic reaction. The optimal molar ratio of ZnO/ZnMgAl-CO3-LDHs for the photocatalysis is 3. The heterojunction photocatalyst ZnO/ZnMgAl-CO3-LDHs may be a promising photocatalyst for future application in water treatment due to its excellent performance in degradation of phenol.