Preparation of TiO2 Nanocrystalline Powder with High Specific Area Using Urea as the Template

TiO₂ nanocrystalline powders with high specific area were prepared using urea as the template by the sol-gel method. The samples were characterized by X-ray diffraction, N₂ adsorption isotherms, and transmission electron microscopy. Urea plays a key role in the preparation process of TiO₂ nanocrystalline powders. Large amounts of small urea aggregates were formed in the sol-gel process and decomposed during the calcination process, which results in the formation of large amounts of mesopores. Urea also inhibits the agglomeration and growth of the TiO₂ nanoparticle, which facilitates the preparation of a TiO₂ powder with smaller nanocrystal size. The above effects of urea may be the main reason of the as-prepared sample with very high specific surface area.