Ultra Efficient 4-Nitrophenol Reduction, Dye Degradation and Cr(VI) Adsorption in the Presence of Phytochemical Synthesized Ag/ZnO Nanocomposite: A View Towards Sustainable Chemistry

Silver (Ag) doped zinc oxide (ZnO), an efficient photocatalyst was synthesized by facile method using Capparis decidua plant extract as natural reducing agent. To explore deeply into the structural morphologies and applications various amounts of Ag were doped on the surface of ZnO. The successful synthesis of nanomaterials was confirmed by UV-Vis, XRD, SEM, HRTEM, FTIR, DLS and XPS. The enhanced catalytic potential of Ag-ZnO was examined by 4-nitrophenol (4-NP) reduction, methylene blue degradation and chromium (VI) ion adsorption from aqueous solution, under UV-visible light in a semi batch reactor. These experiments suggest that Ag doping to ZnO enhances photocatalytic potential by limiting the drop back probability of electrons from conduction to valence band. To get best results, experimental condition such as pH, catalyst dose, analyte initial concentration, contact time were optimized. Additionally, the role of Ag in improvement of semiconducting properties and mechanism of degradation and reduction were explained. The adsorption process revealed optimal correlation with the Freundlich model and pseudo second order kinetics. Consequently, the negative value of Delta G degrees and positive values of both Delta H degrees and Delta S degrees indicate that the adsorption process is spontaneous, endothermic and physical in nature. It is anticipated that synthesis of Ag/ZnO nanocomposite was a cost effective and green approach, which provided significant photocatalysis ability.