Sun-light-driven photocatalytic activity by ZnO/Ag heteronanostructures synthesized via a facile thermal decomposition approach

Abstract

ZnO/Ag heteronanostructures with varying amounts of silver nanoparticles on ZnO nanorods were successfully synthesized via a novel and economical thermal decomposition approach. ZnO nanorods were first synthesized by a homogeneous precipitation method and silver nanoparticles were subsequently deposited on the surface of ZnO nanorods by the thermal decomposition of silver acetate in diphenyl ether at 220 °C. The amount of silver nanoparticles on the ZnO nanorods was controlled by varying the concentration of silver acetate during the thermal decomposition. The synthesized ZnO/Ag heteronanostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDXA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. XRD results confirm the presence of silver nanoparticles (size = 24–31 nm) in the ZnO/Ag heteronanostructures. SEM and TEM images prove the presence of silver nanoparticles on the surface of ZnO nanorods. XPS results indicate the presence of metallic silver in ZnO/Ag. DRS results show characteristic surface plasmon resonance absorption due to silver nanoparticles and PL results indicate an effective separation of photogenerated electron–hole pairs in the ZnO/Ag heteronanostructures as compared to pristine ZnO nanorods. The synthesized ZnO/Ag heteronanostructures were explored as a catalyst towards the photodegradation of methylene blue in an aqueous solution and photostability of the ZnO/Ag heteronanostructures has also been demonstrated.