Photocatalysis of Nickel-Based Graphene/Au/ZnO Nanocomposites

Gold (Au) nanoparticles were deposited on the 3D Nickel (Ni)/graphene composites by soaking the composites in the Au nanoparticles solutions and the ZnO nanostructures with different morphologies were fabricated on Ni/graphene/Au by the hydrothermal processing. The photocatalytic performance of Ni/graphene/Au/ZnO nanocomposites was investigated and the one with ZnO nanoplates exhibited optimal photocatalytic performance toward methyl orange (MO) under simulated sunlight, revealing superior apparent degradation rate constant K-app about 1.5-fold higher compared with that of the nanocomposite without Au incorporated. The influence of Au nanoparticles and hydrothermal processing time on the ZnO nanostructures morphology and structure as well as the photocatalysis mechanism were discussed in detail. The incorporation of Au nanoparticles induced reduction of ZnO bandgap due to the generation of remarkable valence band tail states, and ZnO crystallinity revealed a strong dependence on its morphology. Meanwhile, the combining effect of incorporation of Au nanoparticles and optimization of ZnO nanostructures morphology would not only facilitate the electron transfer from ZnO to Au but also enhance the photo-generated electron storage, suppressing the electron-hole pairs recombination and improving the photocatalytic performance. The study provided an easy-handling way for the fabrication of noble metal incorporated, hybrid carbon-semiconductor-based photocatalysts.