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 work focuses on the study of effect of Cd-doping on the structural, optical, and photocatalytic degradation efficiency of methylene blue (MB) and methylene orange (MO) dyes on ball-milled cum solid-state reaction synthesized copper oxide (CuO) nanoparticles. X-ray diffraction reveals the presence of a monoclinic CuO phase only, which confirms the successful doping of Cd in the CuO matrix. The XRD and TEM analysis suggests the shrinkage of particle size (47 to 40 nm) of CuO nanoparticles with increase of Cd-doping content. The optical studies also reveal the narrowing of CuO band gap from 3.48 to 3.43 eV with increase of doping percentage. XRD and PL analysis confirms the enrichment of structural defects of CuO lattice with introduction of dopant into it. Further, the DFT + U approach was used for crystal structure, state of density, and band structure evaluation. The sunlight-driven photocatalytic degradation activity of the samples was tested against pollutants (MO and MB dyes). The degradation efficiency of CuO nanoparticles was found to be 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. This excellent performance of Cd-doped CuO nanostructure makes it an appropriate candidate for various environmental applications such as removal of water pollutant. Graphical abstract