Physico-chemical characterization and photocatalytic activity of zinc oxide prepared by various methods

Zinc oxide was prepared by different methods by varying precipitating agents, the source of the salt precursors and the microwave irradiation time and was characterized by XRD, BET-surface area, surface acidity and crystallite sizes. The photocatalytic reactions were carried out under solar radiation in batch reactors towards oxidation of 4-nitrophenol and reduction of Cr(VI) by varying different parameters such as irradiation time, pH of the solution, catalyst amount and substrate concentration and the activities were correlated with the physico-chemical parameters. Zinc oxide samples prepared by microwave irradiation and calcined at 300 °C exhibit highest surface area, acid sites and lowest crystallite sizes and show highest activity towards photocatalytic reactions.

Microwave irradiation has beneficial effect on photocatalytic activity of ZnO. Microwave irradiated sample heated at 300 °C shows more surface area, less crystallinity size and hence it shows better activity among all the samples. Under optimization of reaction conditions, 15 min microwave irradiated sample in 0.6 g/L dose shows 92 and 98% photodegradation of 4-nitrophenol and photoreduction of Cr(VI), respectively.Figure optionsDownload as PowerPoint slide