Experimental and DFT+U investigations of the Cu 1-x Cd x O nanoparticles synthesized for photocatalytic degradation of organic pollutants: Environmental Application

The present investigation focuses on the impact of Cd-doping concentration on the structural, optical and photocatalytic degradation properties of the CuO nanostructures. Cd-doped (0, 1 and 3 mol %) CuO nanostructures were synthesized using ball milling cum solid-state reaction method. The physical properties of nanostructures were investigated using Raman, TEM, ultraviolet–visible, photoluminescence spectroscopy, X-ray diffraction, and dynamic light scattering techniques. X-ray diffraction and Raman spectroscopy detect the presence of a monoclinic CuO phase only, which confirms the successful doping of Cd in the CuO matrix. A decrease in particle size with doping has been disclosed by XRD, dynamic light scattering and TEM studies. XRD and PL studies reveal the enhancement in structural defects with doping concentration. Further, the DFT + U approach was used for crystal structure, the density of states and band structure evaluation. The sunlight-driven photocatalytic degradation activity of the samples was tested against organic pollutants (methylene orange (MO) and methylene blue (MB) dyes). The degradation efficiency of the CuO nanoparticles was found to the enhanced with Cd-doping concentration. 3 mol% doped Cd-CuO, shows the best degradation efficiency and successfully degrades 59% and 75% of MO and MB dyes in 240 min under sunlight irradiation. Our samples exhibit a pseudo-first-order kinetic model and the rate constant is found to increase with Cd-doping. Thus, Cd-doped CuO nanostructures possess good candidature for environmental applications.