Silver imprinted zinc oxide nanoparticles: Green synthetic approach, characterization and efficient sunlight-induced photocatalytic water detoxification

Unique and infrequent strategy to greenly synthesize silver imprinted zinc oxide nanoparticles (AgZnO NPs) is presented. A facile and low cost phytosynthetic route using guava leaves aqueous extract succeeded in decorating commercial ZnO with Ag nanoparticles without needing environmentally undesirable chemical reagents. The AgZnO NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet/visible (UV/Vis) spectrophotometry/spectrofluorimetry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Band gap calculations of Ag(2.5mol%)/ZnO give estimate of (3.03 eV) compared to 325 eV for ZnO. indicating good capacity of visible light absorption. This improves the solar energy harvesting characteristics of the phyto-developed AgZnO NPs. Moreover, the photocatalytic efficacy of AgZnO NPs is tested in detoxification of methylene blue (MB) enriched aqueous solutions. Parameters affecting the photodegradation rate like catalyst dosage, amount of Ag loading and pH were investigated and optimized. Under approximate to 18 min of sunlight irradiation (800 W/m(2)), over 22 mg/L of alkaline solution of MB can be efficiently photomineralized using 0.4 g of Ag(2.5%)/ZnO NPs. Under the optimized conditions, the developed photocatalysts show a great stability after 6 folds of photocatalytic cycles reflecting their efficient photocatalytic performance in the long run. (C) 2018 Elsevier Ltd. All rights reserved.