Fabrication of Cu doped ZnO nanocrystals hybridised with Graphene oxide nanosheets as an efficient solar light driven photocatalyst for the degradation of Quinalphos pesticide in aqueous medium

This present study involves the sonochemical and microwave synthesis of an efficient light harvesting nanocomposite photocatalyst, ZnO/GO embedded with copper nanoparticles. The synthesised nanocomposite was characterised by various spectroscopic methods like XRD, SEM, EDX, FT-IR, UV-DRS and fluorescence analysis. The catalytic activity of the synthesised nanocomposite was tested using an organophosphorous pesticide, as the test solution and its percentage efficiency of degradation were studied. About 99 % of 40 ppm of Quinalphos pesticide could be degraded using ZnO/Cu/GO nanocomposite (3 mg/L) under visible light radiation within20 min at neutral pH. The presence of an intrinsic defects and the fluorescence property of the prepared nanocomposite were also detected. The degradation efficiency was estimated by COD and TOC measurements. The reaction rate followed pseudo - first order kinetics with a rate constant of 0.042 min-1. Furthermore, the composite has demonstrated a reusable feature and was utilised for eight cycles without any change in its activity. These findings has illustrated an ecofriendly, more stable and well organised photocatalytic nanocomposite, which could be preferred much for the treatment of industrial and agricultural waste water containing organic contaminants within a short span of time under irradiation using sunlight.