ZnO-Cu2O Composites for Photocatalytical Removal of Methylene Blue from Aqueous Solution under Visible Light

Abstract

ZnO-Cu₂O composites were prepared by precipitation technique followed by calcination. The prepared composite was characterized by scanning electron microscopy (SEM), energy dispersion X-ray (EDX), Fourier transform infra-red (FT-IR) and X-ray diffraction (XRD). Band gap energy of the composite was determined by UV-visible reflectance measurement. The absorption range of the ZnO-Cu₂O composite was shifted to the visible region due to the doping of Cu₂O. SEM image represented that composite nanoparticle was smaller in size compared to the pure ZnO. The EDX spectral analysis showed that no elements other than Zn, Cu and O were present in the sample. XRD showed that ZnO-Cu₂O composite was made of hexagonal ZnO and cubic Cu₂O. The photocatalytic activity of ZnO-Cu₂O composite was studied by degrading MB under different experimental conditions. The molar ratios of the composites, amount of the composite, initial concentration of dyes were varied to optimize the conditions for degradation. The experimental result was compared with those of commercial ZnO. It was found that the ZnO-Cu₂O composite is a better photocatalyst than ZnO under visible light.

Dhaka Univ. J. Sci. 71(1): 42-48, 2023 (Jan)