Crystallization of Titania in Methanol, N-Hexane and Water at High Temperatures

Amorphous TiO₂ was prepared by dissolving TiCl₄ to NH₄OH-CH₃OH-H₂O mixed solution and hydrolysis of titanium(IV) tetraisopropoxide. Microcrystalline anatase was fabricated by crystallizing amorphous TiO₂ gels in methanol, N-hexane and water at 120~200°C which were much lower than the crystallization temperature in air. The crystallization behavior could be adequately described by the surface chemical reaction controlled shrinking core model. Crystallization in water was much faster than in methanol and n-hexane, but the sinterability of powder prepared in water was poorer than of that prepared in organic solvents. The addition of requisite amounts of water to organic solvents was found useful in promoting crystallization of gel without loss of powder sinterability.