Fabrication of a highly efficient CuO/ZnCo2O4/CNTs ternary composite for photocatalytic degradation of hazardous pollutants

Abstract

In the current study, CuO, ZnCo₂O₄, CuO/ZnCo₂O₄, and CuO/ZnCo₂O₄/CNTs photocatalysts were prepared to remove crystal violet (CV) and colorless pollutants (diclofenac sodium and phenol) from wastewater. Herein, sol–gel and co-precipitation methods were used to synthesize CuO and ZnCo₂O₄, respectively. The sonication method was used to synthesize CuO/ZnCo₂O₄ and a CNTs-based composite (CuO/ZnCo₂O₄/CNTs). From the UV-Vis spectra of CuO, ZnCo₂O₄, CuO/ZnCo₂O₄, and CuO/ZnCo₂O₄/CNTs, the optical band gap value was calculated to be 2.11, 2.18, 1.71 and 1.63 eV respectively. The photocatalytic results revealed that CuO/ZnCo₂O₄/CNTs exhibited higher degradation of 87.7% against CV dye, 82% against diclofenac sodium, and 72% against phenol as compared to other prepared photocatalysts. The OH˙ radical is identified as the active species in the photocatalytic process over CuO/ZnCo₂O₄/CNTs. The impact of several parameters, such as pH, concentration, and catalyst dosage, has also been investigated. The better activity of the CNTs-based composite was due to the synergic effect of both CuO/ZnCo₂O₄ nanocomposite and carbon nanotubes. Therefore, the synthesized CuO/ZnCo₂O₄/CNTs photocatalyst has the potential to degrade organic wastewater effluents effectively.