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

Abstract 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.