Abstracto

Synthesis of silver incorporated ZnO nanostructures by different methods and investigation of their photocatalytic and antibacterial efficiency

B.Divband, M.Khatamian

In this paper, Ag/ZnO photocatalysts with different Ag loadings were prepared by photo reduction, chemical reduction and polyacrylamide-gel methods. TheAg/ZnO photocatalysts were characterized by XRD, SEM, TEM, EDX andDRUV-vismethods. The results of the photocatalytic degradation of 4-NP in aqueous suspensions showed that silver ions doping greatly improved the photocatalytic efficiency of ZnO nanocrystallites. The enhancement of photocatalytic activity is due to the fact that the modification of ZnO with an appropriate amount of Ag can increase the separation efficiency of photogenerated electrons and holes in ZnO, and the improvement of photo stability of ZnO is attributed to a considerable decrease of the surface defect sites of ZnO after the Ag loading. The chemisorptions ofmolecular oxygen and the chemisorption of atomic oxygen on Ag in the Ag/ZnO photocatalysts were observed. It was found that the metallicAg in theAg/ZnO photocatalysts does play a new role of O2 chemisorption sites except for electron acceptor, bywhich chemisorbed molecular oxygen reacts with photogenerated electrons to form active oxygen species, and thus facilitates the trapping of photogenerated electrons and further improves the photocatalytic activity of the Ag/ZnO photocatalysts. Also the method of preparation is regarded as important factors for determining photocatalysis. The best photocatalytic performance was exhibited forAg/ZnO prepared by polyacrylamide gel method in comparison with chemical reduction and photo reduction method and the optimumAg content was approximately 0.5%.With the appearance of microbial organisms resistant to multiple antibiotics, also, increase nosocomial infection, antibacterial effects of nanocomposites have attended by the many researchers in recent years. In the present work, the antibacterial properties of Silver incorporated zinc oxide nanoparticles were investigated using Escherichia coli.