BENZYLTRIMETHYLAMMONIUM CHLORIDE IMMERSION EFFECT ON PHYSICAL PROPERTIES OF TiO2 – Al203

Abstract

BENZYLTRIMETHYLAMMONIUM CHLORIDE IMMERSION EFFECT ON PHYSICAL PROPERTIES OF TiO 2 – Al 2 O 3 . Mesoporous TiO 2 - Al 2 O 3 powders have potential applications in catalysts or support catalysts. A novel method to control pore size of sol--gel by a cationic surfactant benzyltrimethylammonium chloride (BTAC) Immersion was investigated. The gels of TiO 2 - Al 2 O 3 in molar ratio of 0.2 of TiO 2 , and 0.8 of Al 2 O 3 were prepared by hydrolysis of aluminium sec-butoxide, Al(OC 4 H 9 sec ) 3 and titanium isopropoxide Ti(OC 3 H 7 iso ) 4 in an n-propanol solution with acid catalyst. The structures and porosities of the modified TiO 2 -A| 2 O 3 was depended on the dimensions of surfactant, as long as the calcination was carried out at 500℃ to avoid aggregation process during removal of excess BTAC. If the calcinations were carried out at 800℃ no significant change of the pore volume of modified samples was remarkably not observed, even though formation of TiO 2 rutile has been taken place. It indicated that samples modification by initial immersion of gel into BTAC may avoid the sintering. These results suggest that during the calcinations TiO 2 , was segregated from the Al 2 O 3 particles to form nuclei of rutile and was crystallized prior to formation of α- Al 2 O 3 . Therefore, the formation of rutile TiO 2 induced the formation of α- Al 2 O 3 .