The effects of different acids on the preparation of TiO2 nanostructure in liquid media at low temperature

Titania of different crystalline structures and morphology was prepared by the low temperature dissolution–reprecipitation process (LTDRP) of amorphous precursors in various acidic mediums at 70 °C for 8 h. The effects of different acids on the crystalline and morphology of titania nanostructures were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results showed that HCl, HNO₃ and their mixture favored the formation of rod-like rutile TiO₂, while H₂SO₄ and its mixture with HCl or HNO₃ retarded the formation of rutile but favored the formation of the anatase phase of with an irregular shape. The mechanism of the formation of various titania nanostructures was also discussed.