Modified Ag-ZnO coated graphene oxide ternary composite for superior photocatalytic degradation of crystal violet dye under visible light irradiation

Abstract

The enhancement of advanced nanomaterials into photocatalytic applications has preserved a significant curiosity for its potential to address environmental challenges. To address this concern, a green and eco-friendly catalyst was fabricated. In this study, we examined the enhancement of the photocatalytic activity of various synthesized composites with the modification of graphene oxide (GO) and Ag over the surface of semiconductor zinc oxide (ZnO). The simple wet chemical method was used for the synthesis of ZnO, GO(x)@ZnO, Ag2@ZnO and GO(x)Ag2-ZnO composites [x = 1,3,5 wt%]. The synthesized samples were characterized by different techniques such as XRD, SEM-EDS, DRS, Raman, and PL. Ternary GO5@Ag2-ZnO photocatalyst exhibited superior degradation efficiency up to 97 % in degrading crystal violet (CV) dye, a persistent and environmentally concerning pollutant under visible light irradiation. The significant photocatalytic activity was attributed to the surface plasmon resonance (SPR) phenomenon of Ag, whose broad absorption band was observed in DRS, better electron mobility, and a large surface area of GO facilitates the charge transfer. The highly efficient catalyst was effectively employed for five repeating cycles with only an 11 % decrease in removal rate, demonstrating that it can be easily reused. Kinetic study reveals that the prepared composite follows a pseudo-first-order reaction model with the highest rate constant value of 0.02491 min−1 respectively. The possible degradation pathway was determined using the HRMS technique.