Tailored Synthesis and Detailed Characterization of Ni–Mg Co-doped CuO Nanostructures for Photocatalytic Degradation Efficiency

Abstract

In this study, we synthesized and investigated the influence of dopant nature on copper oxide nanoparticles (NPs) for four compositions: undoped CuO, Ni-doped CuO (Cu_0.95Ni_0.05O), Mg-doped CuO (Cu_0.95Mg_0.05O), and (Ni,Mg) co-doped CuO (Cu_0.90Ni_0.05Mg_0.05O), using the sol–gel method. Samples were characterized through various characterization techniques and by photocatalytic performance. X-ray diffraction (XRD) analysis confirmed single-phase monoclinic CuO structure. (Ni,Mg) co-doping significantly reduced the average crystallite size from 20.95 to 6.24 nm. Scanning electron microscopy (SEM) demonstrated that the incorporation of Ni and Mg affected the morphology of the CuO NPS. Fourier-transform infrared (FTIR) spectra confirm the formation of CuO NPs. Moreover, (Ni,Mg) co-doping generated a synergistic electronic effect, where Ni narrowed and Mg widened the band gap, yielding an optimized band structure, improved light absorption in both the visible and UV ranges. This tunability is advantageous for photocatalytic applications, as the broader spectral response improves light harvesting and, consequently, photocatalytic efficiency.