Preparation of Ultrafine Crystalline TiO₂ Powders from Aqueous TiCl₄ Solution by Precipitation

Abstract

Ultrafine crystalline TiO2 powders were prepared by just heating and stirring aqueous TiOCl2 solution with a Ti+4 concentration of 0.5 mol/l at room temperature to 100°C under one atmosphere. The crystallinity, the phase transformation and the particle shape of ultrafine TiO2 powders obtained by this simple precipitation method were analyzed using an X-ray diffractometer (XRD), transmission electron microscopy (TEM), differential thermal analyzer (DTA), and scanning electron microscopy (SEM). TiO2 crystalline precipitates with a pure rutile phase were formed below 65°C, then TiO2 crystalline precipitates with an anatase phase started forming at temperatures higher than 65°C, which ends with the pure anatase phase at 100°C. The direct formation of TiO2 crystalline precipitates from an aqueous TiOCl2 solution is due to the existence of the OH- ions in distilled water which cause the crystallization of TiOCl2 to TiO2 without hydrolyzation to Ti(OH)4. Conventionally, rutile-phase TiO2 is obtained at much higher temperatures. However, in this study a stable rutile-phase TiO2 was obtained by a simple method at close to room temperature.

Influence of Crystallite Size of TiO2 Supports on the Activity of Dispersed Pt Catalysts in Liquid-Phase Selective Hydrogenation of 3-Nitrostyrene, Nitrobenzene, and Styrene

“…Recently nano-sized TiO2 materials have been attracting a growing interest in their unique catalytic actions, in particular, in photocatalytic reactions [2]. The nano-sized TiO2 materials are prepared by several methods such as solvothermal [3][4][5], precipitation [6], sol-gel [7][8][9], and thermal decomposition [10] methods.…”

Low temperature synthesis of anatase and rutile titania nanopowders by hydrolysis of TiCl4 using ammonia gas

“…Nam et al has studied the ultrafine crystal titania powders from aqueous TiCl 4 solution. They found that as-precipitates with pure rutile phase were formed below 65 • C. If the temperature is over 65 • C, the anatase phase begins to form as the formation of rutile phase, and pure anatase phase obtained at 100 • C [21]. The fabrication of pure anatase titania lower than 65 • C could hardly be performed.…”

Piezoelectric Characteristics of Chiral Polymer Composite Films Obtained under Strong Magnetic Field

“…For the experiment on the effect of strong magnetic field, we use TiO 2 . Because it has been reported that TiO 2 is not affected by a strong magnetic field, 12,13) we include PLLA/Hap and PLLA/TiO 2 for comparison. The shear piezoelectric constants of drawn PLLA, PLLA/Hap(2), PLLA/Hap(5) and PLLA/TiO 2 membranes are summarized in Table I.…”