Microwave assisted sol–gel synthesis of titanium dioxide using hydrochloric and acetic acid as catalysts

Abstract Titanium dioxide (TiO 2 ) was synthesized by microwave assisted sol–gel. The effect of the acid type used as catalyst on the phase transformation of TiO 2 was investigated (hydrochloric or acetic acid). The samples obtained were characterized by scanning electron microscopy (SEM), this micrographs showed particles with irregular shapes. The results of Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) showed present signals of O and Ti. When hydrochloric acid was used as catalyst, three titania polymorphs were detected by X-ray diffraction (XRD), anatase, rutile and brookite, where the crystallite size was in the range of 9 and 16 nm. On the other hand, a single anatase phase was formed when acetic acid was used after only 15 min of reaction time. The anatase average crystallite size was obtained between 11 and 22 nm.