A simple and green photoreduction approach for synthesis of Au/g-C3N4 hybrid nanocomposites with high solar light photocatalytic activity

In this study, we developed a green and easy to scale up approach for producing Au/g-C3N4 (Au/GCN) hybrid plasmonic photocatalyst without using the chemical reducing agents via the growing of Au nanoparticles (Au NPs) on the surface of GCN nanosheets under the photo-reduction of ultraviolet (UV)-radiation. Different characterization techniques were conducted for investigating the structure, morphology, surface chemistry and optical properties of the as-prepared catalysts. The scanning electron microscope image shows that the homogeneous Au NPs anchored on the surface of the GCN nanosheet increased with the UV illumination time. The x-ray photoelectron spectroscopy results prove the coexistence of GCN nanosheets with heptazine heterocyclic ring (C6N7) units and Au NPs in the Au/GCN. The photoluminescence intensity decreased sharply with the time of UV irradiation, indicating that the recombination rate of photogenerated electron-hole recombination decreased. The photocatalytic activity of the hybrid catalysts was evaluated by degrading rhodamine B (RhB) under simulated sunlight irradiation. The results show that the Au/GCN photocatalyst exhibits superior sunlight photocatalytic activity than that of bare GCN. The 6 h irradiated fabricating sample exhibited the strongest photocatalytic activity, completely decomposing the 10 ppm RhB in 30 min of irradiation. This report can provide the design of a simple and green synthesis method for the highly active Au/GCN photocatalyst.