Impact of Nickel and Cobalt Incorporation on the Band Gap of Copper Oxide Nanoparticles

Abstract

The study focuses on the change in the optical band gap of the nickel and cobalt-doped copper oxide nanoparticles and compares the same with pure copper oxide nanoparticles. Four sets of pure and doped copper oxide nanoparticles were prepared as pure copper oxide (CuO), Nickel doped copper oxide (Ni/CuO), cobalt-doped copper oxide (Co/CuO) and, nickel-cobalt co-doped (Ni-Co/CuO NPs). All the nanoparticles were prepared with a simple co-precipitation method. The samples were characterized with UV-visible spectroscopy, photoluminescence spectroscopy, and zeta potential measurement. For the calculation of optical band gap, two methods were followed, Tauc’s method using UV-visible absorption spectra and photoluminescence emission. The band gap calculated with absorption spectra was found to be lower than that calculated with emission spectra. From zeta potential measurements, it was found that the copper oxide nanoparticles had more stability when incorporated with nickel. The samples were tested for the photocatalytic degradation of malachite green (MG). Increased band gap of copper oxide nanoparticles offers potential improvement in the photocatalytic activity of copper oxide nanoparticles.