Photoluminescent and photocatalytic properties of Cu2+ and Mg2+-doped ZnO nanoparticles obtained by a facile sonochemical method

Pure ZnO particles, doped and co-doped with Cu²⁺ and Mg²⁺ ions, were obtained by the simple sonochemical method. The wurtzite hexagonal structure was confirmed by X-ray diffraction (XRD) patterns. The images obtained by field emission scanning electron microscopy (FE-SEM) showed irregular and more agglomerated particles with the increase of Cu²⁺ and Mg²⁺ ions concentration in the ZnO lattice, with the average diameter of particles in the range of 57.23–170.77 nm. The photocatalytic activity was investigated by decolorizing the methylene blue (MB) dye under ultraviolet C (UVC) light irradiation which indicates that 1% Mg-doped ZnO particles have better the photocatalytic activity than the other samples, and presented the highest kinetic constant value. The co-doped samples showed a reduced global surface area which did not favor the good photocatalytic performance. The sacrificial agents showed that OH• radicals are the main species involved in the photocatalytic activity of this system and defects generated in the ZnO lattice promoted photoluminescent emission in the red and green regions.