Investigating the photocatalytic activity of hybrid ZnO@TiO₂ nanocomposites towards dyes degradation

In the present study ZnO@TiO₂ nanocomposites were obtained simply mixing home prepared ZnO and commercial TiO₂ (P25) by a ball milling apparatus. ZnO was synthesized by a hydrothermal method by using zinc acetate dihydrate as Zn²⁺ precursor, polyvinyl pyrrolidone as surfactant and water or ethylene glycol or triethylene glycol as solvent. Structural and optical characterizations were performed 03 using techniques such as X-Ray Diffraction (XRD), Scanning (SEM) and Transmission (TEM) Electron Microscopy, Diffuse UV–Visible spectroscopy (DRS) and Specific Surface Area (SSA) determinations, while electrochemical measurements were made to get insight into the electronic properties of the photocatalysts. The photocatalytic degradation of two model pollutants, i.e., Rose Bengal and Rhodamine B, was carried out to investigate the performances of the nanocomposites prepared at different ZnO/TiO₂ ratios. The hybrid samples displayed higher activity than bare ZnO and TiO₂ ascribable to the enhancement of the charges transfer process. The results obtained in the presence of scavenging agents demonstrated that the active species (h⁺, e⁻, ^•OH, and O₂^•-) work together to degrade dyes.