Synthesis and characterization of nanoestructured TiO2 anatase-phase powders obtained by the homogeneous precipitation method

Abstract

Titanium dioxide (TiO2) nanoparticles were synthesized by the homogeneous precipitation method using titanium (IV) butoxide as Ti precursor. The solution was prepared by dissolving 26 ml of titanium (IV) butoxide in a mix of ethanol, glacial acetic acid, and sulfuric acid (53:43:4 ml, volume proportion), under constant magnetic stirring at 55 °C, until having a white precipitate. This precipitate was centrifuged, decanted, and finally dried at 100°C for two hours. The resultant product was thermally annealed at different temperatures and times, namely, 450, 550, 600, and 650 °C for 6, 12 and 24 h, respectively. Finally the powders were milled at 400 rpm in a planetary ball milling at different times, 2, 6 and 8 h. All powders were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). All the X-ray spectra confirmed the existence of anatase phase. From the XRD spectra, the crystallites size was estimated by using the Scherrer's fomula, giving values in an interval of 18 to 22 nm. The SEM micrographs showed a uniform particle distribution, with a spherical shape. The particle size was measured by TEM and SEM, which oscillated from 20 to 35 nm.