Visible light assisted surface plasmon resonance triggered Ag/ZnO nanocomposites: synthesis and performance towards degradation of indigo carmine dye.

Abstract

Water pollution caused by organic compounds, generated from different industries, has gained attention worldwide today. In this regard, significant efforts have been made for a suitable dye degradation technology. Zinc oxide (ZnO)-based photocatalysts are considered novel materials to degrade organic effluents in contaminated water. The facile synthesis of Ag/ZnO nanocomposites and its application for the enhanced degradation of indigo carmine (IC) dye under visible light irradiation is reported in this paper. The prepared photocatalysts were characterized using various analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron (XPS) spectroscopy, FTIR, Raman, impedance study, UV-Vis, and photoluminescence (PL). Prepared Ag/ZnO nanocomposites were tested for degradation of IC dye in visible light. The degradation efficiency of IC dye was found to be 95.71% in 120min, with a rate constant of 0.02021min-1. This improved photocatalytic activity of Ag/ZnO nanocomposites was mainly due to the absorption of visible light caused by surface plasmon resonance (SPR) derived from Ag nanoparticles (NPs) and electron-hole separation. Radical trapping experiments suggest that holes (h+) and superoxide radical (O2•-) are the key factors in photocatalytic IC dye degradation.