Preparation and Characterization of Undoped and Transition Metal Doped TiO2 Nanoparticles for the Photocatalytic Degradation of Phthalate Esters

Abstract

Photocatalysis is a series of light induced advanced redox reaction processes resulting in the degradation of organic pollutants in presence of oxygen and water. Photocatalytic degradation has attracted considerable attention in the field of waste water treatment due to its capacity to destroy contaminants under mild conditions. However, photocatalytic reactions using the traditional TiO2 photocatalyst suffer from low energy efficiencies under solar irradiation. The low efficiency in the utilization of solar energy lies in its ability to absorb visible light and the high recombination rate of electron-hole pairs. This research is focused on the design of undoped and visible light active transition metals doped TiO2 photocatalysts. These photocatalysts are used for the photocatalytic degradation of phthalate esters. Phthalate esters are the emerging organic pollutants having very harmful effects on human health. In the present work, undoped TiO2 nanoparticles of different sizes are prepared via sol gel method at different calcination temperatures. Doping of Fe, Cu and Ni metal into TiO2 is done, separately using sol-gel technique. Doping is confirmed by characterizing the nanoparticles and the changes observed in their results. Doped samples show enhanced photocatalytic activity as compared to undoped TiO2. The codoping of Fe and Cu into TiO2 is also done. The structural, optical and thermal properties of the samples are investigated by X-ray diffraction (XRD), UVVis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Thermogravimetric analyser (TGA), High resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) techniques. All the prepared samples (doped and codoped) have shown better degradation of diethyl phthalate compared to unoped sample.