Solar-light-driven photodegradation of organic dyes on sono-dispersed ZnO nanoparticles over graphene oxide: Sono vs. conventional catalyst design

Abstract

In this research, ZnO/graphene oxide nanocomposite is prepared by a simple sono-dispersion method as a high performance photocatalyst for the process of organic dye removal from water. The effects of graphene oxide and sonication on the properties of the synthesized samples are studied and were compared with physicochemical properties of ZnO, ZnO/graphene oxide (ZnO/GO) that synthesized via precipitation method (ZG-P) and sono-precipitated method (ZG-SP). X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), the Brunauer-Emmet-Teller (BET) surface area, UV-Vis Diffuse Reflectance Spectroscopy (DRS), Fourier Transform Infrared spectroscopy (FTIR) and UV-Vis spectrophotometer analyses are used to investigate the properties of the samples. High surface area and pore volume, narrow size and uniform distribution of particles and improvement in optical properties are the improved properties due to ultrasound utilization in the synthesis procedure. These improved properties can have a positive effect on photocatalyst performance. Methylene blue, malachite green and eosin yellow as coloured materials and ciprofloxacin as a colourless organic material have been used as water pollutant and their degradation efficiency by the prepared photocatalyst is studied. The effect of initial pH, photocatalyst dosage, initial dye concentration and photostability of ZG-P and ZG-SP samples are examined in this work. It is observable graphene oxide as a carbon allotrope with the oxygenic functional groups has an electron acceptor role, which prevents electron-hole recombination and enhances photocatalyst reusability.