Green synthesis of silver nanoparticles using wolfberry fruits extract and their photocatalytic performance

Spherical Ag nanoparticles (NPs) was synthesized using the Chinese wolfberry fruits extract (WFE) as surfactant and reductant. The hydrolysis time and the reaction time were systematically investigated. The whole synthesis process must be kept boiling in order to enhance the reducing ability of WFE and decrease the reaction time. Under the optimized hydrolysis time of 10 min, the reaction time just need 5 min. Ag NPs were characterized by means of UV-vis, EDX, TEM, HR-TEM, and SAED. It was found that Ag NPs exhibited the surface plasmon resonance wavelength of 408 nm, a small average size of 12.1 nm, and the face-centered cubic structure. Obtained Ag NPs were used as photocatalyst for the reduction of 4-nitrophenol and revealed a high photocatalytic activity and stability. The rate constant was 0.043 min-1, which suggested the reduction of 4-nitrophenol was fast. Clearly, Ag NPs synthesized in the totally green method have a potential application in the field of the wastewater treatment.