Enhanced photocatalytic activity of Ag–ZnO/RGO nanocomposites for removal of methylene blue

In this work, Ag–ZnO/reduced graphene oxide (Ag–ZnO/RGO) nanocomposites were synthesized by a one-step solvothermal method. The structure, morphology and optical properties of nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscope, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectroscopy and UV–Vis absorption spectroscopy. XRD showed that all the synthesized compounds were hexagonal wurtzite structure with high crystallinity. The Raman spectra and FT-IR spectra showed that graphene oxide was reduced to graphene during the reaction. The UV–Vis absorption spectra proved that the absorption edges of doped ZnO nanocomposites were red shifted and the band gaps became smaller compared to pure ZnO. The photodegradation of methylene blue was investigated in the presence of all the composites. Degradation study revealed that Ag–ZnO/RGO nanocomposites exhibited the highest photocatalytic performance due to a smaller band gap and a lower electron–hole recombination rate.