Zirconia particles were prepared by thermal treatment of zirconium(IV) tetra-n-propoxide (ZNP) in C 2 C 6 glycols (Glycothermal method) at 300°C and morphology and pore structures of the products were examined. Xray diffraction results revealed that nanocrystals of tetragonal zirconia phase were mainly obtained in all cases. However, the morphology and pore structures of the products were quite different depending on the glycols used. The products prepared in 1,4-butanediol (1,4-BG) were spherical particles with ca. 5¯m size while aggregations of fine particles were observed for other glycols. The samples obtained in 1,4-BG had large surface areas and showed narrow pore-size distributions in the mesopore region. To investigate the formation process of the products having such a unique morphology and pore system, the mixtures of ZNP and glycols were heated at lower temperatures. It was found that the thermal reaction of ZNP in 1,4-BG at 200°C afforded intermediates with layered structures, which subsequently changed into nanocrystalline ZrO 2 at elevated temperatures. These stepwise crystallization processes attribute to the unique morphology and pore system of the products obtained by the thermal treatment of ZNP in 1,4-BG.

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Titania-modified zirconias with different Ti/Zr ratios were synthesized via thermal treatment of zirconium (IV) tetra-n-propoxide and titanium (IV) tetra-iso-propoxide in 1,4-butanediol at 300 °C. The obtained products were spherical particles composed of nanocrystals with the tetragonal ZrO2 structure. The products had large specific surface areas, large pore volumes, and relatively narrow pore size distributions in the mesopore region. After calcination at high temperatures, the obtained TiO2-modified ZrO2 samples preserved large surface areas and pore structure. Having these superior thermal stability and pore structure, the obtained TiO2-modified ZrO2 particles are expected to show high performance as catalytic materials.

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