Green preparation of Ag-ZnO-rGO nanoparticles for efficient adsorption and photodegradation activity

To improve the photocatalytic performance of ZnO nanoparticles , based on the collective effect as electron sink of Ag and perfect two-dimensional (2-D) feature of graphene, Ag-ZnO-rGO nanoparticles were prepared by polyvinyl alcohol assisted freeze-drying and subsequent hydrothermal reduction method. Through photocatalytic degradation of methyl orange solution under UV irradiation , all as-prepared samples were assessed and compared with those of published works. The surface morphology , microstructure and optical property of materials were systematically studied by XRD , XPS , SEM , TEM and DRS , respectively. XPS and Raman spectra results confirmed that GO has successfully been reduced to rGO; SEM and TEM characterizations manifested that Ag-ZnO NPs were uniformly distributed in rGO with two-dimensional sheets structure; DRS characterization and Kubelka-Munk formula calculation illustrated that Ag-ZnO-rGO exhibited the smallest band gap and the best optical absorption performance. Moreover, the photocatalytic degradation results indicated that Ag-ZnO-rGO NPs combine the advantages of graphene and Ag which not only has significant adsorption but also maintains high photoreactivity.