Synthesis of spherical porous zirconia and titania particles in W/O emulsion

Spherical porous zirconia and titania particles were synthesized by the sol-gel process from zirconyl chloride, zirconium tetrapropoxide and titanium tetraisopropoxide in W/O emulsion, respectively. Zirconia particles are obtained by addition of urea and hexamethylenetetramine in a starting solution, When the molar ratio of zirconyl chloride, calcium chloride, urea, hexamethylenetetramine, N,N dimethyl formamide and H2O is 1 i 0.2 : 1.1 : 0.9 : 1.4 : 45, spherical porous zirconia particles could be synthesized. The particles occurred cubic and monoclinic form at 600 degrees C, respectively. Peak pore-diameter of the particles was 4 nm, The pore volume increases with increase in calcium content. After the extraction of calcium by hot water, the specific surface area of the particles is enhanced 110 m(2)/g. SiO2-ZrO2 binary particles are synthesized by using zirconium tetrapropoxide and 2-methoxyethanol, When the molar ratio of tetramethoxysilane (TMOS), zirconium tetrapropoxide, 2-methoxyethanol, H2O and HCl is 0.7 : 0.3 : 5.25 : 20 : 3.6 x 10(-4), the specific surface area of the particles was 260 m(2)/g. After the extraction of SiO2 parts by 1 M NaOH aqueous solution, the weight loss of the particle was 10 mass%. Titania particles are obtained by addition of diethanolamine or 2-methoxyethanol in starting solution, Peak pore-diameter of the particles is 4 nm when the molar ratio of diethanolamine to titanium tetraisopropoxide was 1.5, By calcination at 500 and 700 degrees C, the particle occurred anatase and rutile type, respectively. TiO2-SiO2 binary particles are synthesized by using 2-methoxyethanol, When the molar ratio of titanium tetraisopropoxide, TMOS, 2-methoxyethanol, H2O and HCl is 0.4 : 0.6 : 4 : 20 : 1.8 x 10(-3), the specific surface area of the particles was 180 m(2)/g after the extraction of SiO2 parts by 0.1 M NaOH aqueous solution.