Synthesis of TiO_2 using different hydrolysis catalysts and doped with Zn for efficient degradation of aqueous phase pollutants under UV light

摘要

In this work, various TiO_2 and TiO_2 doped with 0.1, 1.0, and 5.0 mol% of Zn were prepared by the sol–gel method varying different hydrolysis catalysts (HNO_3, OHAc, H_3PO_4) in order to be used as photocatalysts for environmental applications. The X-ray diffraction results showed that the different TiO_2 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 H_3PO_4, HOAc, and HNO_3 was 245, 100, and 90 m~2 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 TiO_2, 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 m~2 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.