Synthesis of TiO₂ using different hydrolysis catalysts and doped with Zn for efficient degradation of aqueous phase pollutants under UV light

摘要

In this work, various TiO₂ and TiO₂ doped with 0.1, 1.0, and 5.0 mol% of Zn were prepared by the sol–gel method varying different hydrolysis catalysts (HNO₃, OHAc, H₃PO₄) in order to be used as photocatalysts for environmental applications. The X-ray diffraction results showed that the different TiO₂ samples have presented the anatase as main phase, However, the acid nature has played an important role in the superficial and optical properties. The N-physisortion analysis has revealed that the specific surface area of calcined TiO₂ samples prepared using H₃PO₄, HOAc, and HNO₃ was 245, 100, and 90 m2 g−1, respectively, while the spectroscopic UV analysis, the band gap energy has shifted by 3.3–3.0 eV. In order to improve the optical properties of TiO₂, the last preparation was doped with different zinc concentrations. The result showed that, as the Zn concentration increase by 0.1–5.0 mol%, the surface area increased from 90 to 120 m2 g−1. Nevertheless, the E _g returned from 3.0 to 3.32. The SEM analyses have not revealed important morphological changes between no doped and doped materials. The catalytic activity of the composite was studied on the photocatalytic degradation of 2,4-Dichlorophenoxyacetic acid (2,4-D) and the activity results showed that small Zn concentrations decrease the t _1/2 in 28 min.