DEVELOPMENT OF CuO-ZnO COMPOSITE NANOMATERIALS FOR POTENTIAL APPLICATION IN DYE DEGRADATION

Abstract

The photocatalytic efficiency of as-prepared CuO-ZnO composite nanomaterials were investigated towards degradation of congo red (CR) dye in presence of visible light with complete mineralization into less toxic CO2 and water. Herein, Cuo-ZnO composite nanomaterials have been fabricated by electrospinning followed by heat treatment methods i.e. hydrothermal and calcination. The products were characterized using X-Ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), Thermo Gravimetric Analysis (TGA), Transmission Electron Microscope (TEM) and X-Ray Spectroscopy (XPS) for their morphological and structural details. The photocatalytic experiments were conducted for degradation of CR dye under solar irradiation. It was found that photocatalytic reaction followed pseudo first order kinetics from which the rate constants were determined. The experimental results revealed calcined sample showed higher photocatalytic activity in degradation of CR dye as compared to hydrothermally treated sample. This increased efficiency was ascribed to better separation of excited electrons and holes due to development of a p-n heterojunction at the interface of the p-type (CuO) and n-type (ZnO) semiconductors. Photoluminescence studies (PL) were performed to explore separation/recombination rate of photogenerated charge carriers. The optical properties of samples were analyzed using UVVisible NIR spectroscopy. Finally, the reusability studies were carried out up to ten cycles to evaluate stability and viability of multiple utilizations of photocatalysts in the degradation of CR dye. These results unfolded the immense potential of as-prepared CuO-ZnO composite nanomaterials so they can be implemented persistently and efficiently in water remediation in industry.