CoFe2O4/CdS nanocomposite: Preparation, characterisation, and application in sonocatalytic degradation of organic dye pollutants

Abstract

A magnetic CoFe2O4/CdS nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 °C. The nanocomposite was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX), UV-visible spectroscopy, transmission electron microscopy (TEM), N2 gas sorption analysis, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry. The FT-IR, XRD, EDX and XPS results confirmed the formation of the CoFe2O4/CdS nanocomposite. Based on the TEM analysis, the CoFe2O4/CdS nanocomposite constituted nearly uniform, sphere-like nanoparticles of ∼20 nm in size. The optical absorption spectrum of the CoFe2O4/CdS nanocomposite displayed a band gap of 2.21 eV, which made it a suitable candidate for application in sono/photocatalytic degradation of organic pollutants. Accordingly, the sonocatalytic activity of the CoFe2O4/CdS nanocomposite was evaluated towards the H2O2-assisted degradation of methylene blue, rhodamine B, and methyl orange under ultrasonic irradiation. The nanocomposite displayed excellent sonocatalytic activity towards the degradation of all dyes examined—the dyes were completely decomposed within 5–9 min. Furthermore, a comparison study revealed that the CoFe2O4/CdS nanocomposite is a more efficient sonocatalyst than pure CdS; thus, adopting the nanocomposite approach is an excellent means to improve the sonoactivity of CdS. Moreover, the magnetic properties displayed by the CoFe2O4/CdS nanocomposite allow easy retrieval of the catalyst from the reaction mixture for subsequent uses.