Enhanced photocatalytic degradation of crystal violet with hexagonal nanosheets of Cu-doped Co3O4 under UV and visible irradiation

Cobalt oxide nanoparticles are increasingly studied for their low cost and high stability. However, their limited photocatalytic performance, primarily due to faster electron-hole recombination, has prompted extensive research over the past decade. To overcome this challenge, we have synthesized Cu-doped Co3O4 nanoparticles using a facile coprecipitation method at room temperature. The X-ray diffraction (XRD) analysis revealed a reduction in the crystalline size of Cobalt Oxide nanoparticles after doping. FESEM showed porous hexagonal nanosheets as the underlined structure of synthesized Cu-doped Co3O4. FTIR spectra confirmed the spinel structure and high purity of the nanosheets. Brunauer-Emmett-Teller (BET) analysis showed a considerable enhancement in the specific surface area following doping, increasing from 4.21 m2/gm for pristine Co3O4 to 80.75 m2/gm for 7.5% Cu-doped Co3O4. UV-Vis spectra of doped nanosheets showed a red shift in the characteristic absorbance indicating a lowering of the optical band gap. The Tauc plot revealed the optical band gap of the 7.5% Cu-doped Co3O4 to be 2.02 eV in contrast to the 2.41 eV of the pristine Co3O4 nanosheets. Furthermore, UV and visible radiation-induced degradation of Crystal Violet dye was conducted in the presence of the synthesized nanosheets to evaluate their efficiency. Remarkably, the 7.5% Cu-doped Co3O4 exhibited degradation of 92.79% and 97.02% under UV and visible radiation respectively in 20 min. These findings emphasize the influence of the Cu-doping structural, optical and photocatalytic properties of Cobalt oxide nanoparticles under UV as well as visible radiation.