Fabrication of graphene nanosheets decorated by nitrogen-doped ZnO nanoparticles with enhanced visible photocatalytic activity for the degradation of Methylene Blue dye

Abstract

Rapid industrial development has led to an increase in the contamination of water resources due to the discharge of industrial wastewater. In this regard, the contributions of the leather and textile industries are high as they use water in large quantities in their various operations. They release large quantities of wastewater containing a number of toxic organic and inorganic compounds that have become a combined threat to aquatic and human health. Therefore, it is necessary to remove them before they are discharged into the environment or reused through suitable treatment processes. An advanced oxidation process based on semiconductor photocatalysis is considered an emerging technique to overcome this problem. Carbon particles, especially RGO (reduced graphene oxide) materials, are a fascinating electron acceptor/transport material, which has a large surface area and can be applied as photocatalytic materials for energy generation and environmental remediation. Hence, the present investigation deals with novel RGO-N-ZnO, a visible light active nanocomposite photocatalyst prepared by the hydrothermal technique following a modified Hummer's method. The synthesized nanocomposite was characterized to study its various properties by XRD, FT-IR, UV–vis-DRS, FE-SEM, AFM, XPS, and BET analyses. XRD results clearly shows that the prepared nanocomposite possesses a hexagonal wurtzite structure, characteristic of ZnO and is highly crystalline in nature. Raman spectrum provides clear evidence for the doping of N in the prepared RGO-N-ZnO nanocomposite photocatalyst. The specific surface area was found to be 124 m2 g−1 for RGO-N-ZnO nanocomposite. The photocatalytic activity was evaluated for the degradation/oxidation of methylene blue dye under visible light irradiation. RGO-N-ZnO nanocomposite resulted in an enhanced maximum degradation of 98.5% for MB dye molecules after 120 min of visible light irradiation.