Photocatalytic activity of graphene oxide@Ag-ZnO nanocomposite under visible light irradiation

Abstract

The present work outlines on the enhancement of the photocatalytic activity of various synthesized NCs. In this research work, first, we synthesized graphene oxide (GO) using modified Hummer’s method and zinc oxide (ZnO) by simple precipitation method. Further GO@ZnO NCs were prepared by loading of 1-5 wt% of GO onto ZnO by wet chemical method. Then Ag deposited GO@Ag-ZnO nanocomposite was synthesized by photo-deposition method. The prepared catalysts were characterized by different techniques such as XRD, SEM EDS, DRS, Raman, and PL. The broad absorption band of GO@Ag-ZnO composite was observed due to the surface plasmon resonance (SPR) effect of Ag with a reduced band gap value than that of pure ZnO. The GO@Ag-ZnO nanocomposite exhibited outstanding photocatalytic degradation of crystal violet dye (CV). Particularly, GO@Ag-ZnO nanocomposites with GO and Ag contents of 5wt% and 2wt% respectively displayed superior photoactivity up to 97% under visible light irradiation in 2.5 hours, which was substantially better than that was observed for pure ZnO (35%). The pseudo-first-order reaction model was best fitted in kinetics and photocatalytic studies and the rate constants for ZnO, GO5@ZnO, Ag2@ZnO, and GO5@Ag2-ZnO were recorded to be 0.00627, 0.01426, 0.02168 and 0.02491 min- 1 respectively.