Green synthesis of zinc oxide and zinc oxide-silver nanoparticles using olive leaf extract: Photocatalytic dyes degradation, selective organic transformations, and antibacterial activity

In the present study, ZnO and ZnO-Ag nanoparticles were synthesized using a green, simple, and quick method through the utilization of olive leaf extract as a stabilizer and reducing agent. The structural properties, morphological features, and optical characteristics of the as-synthesized pure and composite nanoparticles were thoroughly studied by different experimental and instrumental techniques, such as FTIR, XRD, SEM, TEM, XPS, UV-Vis spectroscopy, etc. ZnO and ZnO-Ag particles in nanosized scales were obtained by properly adjusting the extract concentration, and increasing the extract concentration slightly decreased the resultant particle sizes. The results showed a highly crystalline structure for the synthesized nanoparticles with the wurtzite phase of ZnO and the cubic structure of Ag nanoparticles. The synthesized NPs, especially ZnO-Ag NPs, displayed efficient photocatalytic activity in the degradation of Methylene Blue and Methyl Orange dyes, as well as in the reduction of nitro compounds and synthesizing acetanilids under direct sunlight and LED irradiation. Finally, the ZnO-based nanoparticles showed desired antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Pseudomonas aeruginosa . The results of this work highlight the applications of green-synthesized ZnO and ZnO-Ag nanostructures in various fields, with a particular application role in photocatalytic fine-chemical synthesis under LED irradiation. The results obtained, especially in the context of organic compound synthesis, are of significant importance. It is anticipated that these findings will further enhance and expand the application of green-synthesized ZnO-based semiconductors in selective organic transformations under mild conditions.