High surface area sol-gel alumina-titania nanocatalyst

Abstract

Alumina-titania mixed oxide nanocatalysts with molar ratios = 1:0.5, 1:1, 1:2, 1:5 have been synthesized by adopting a hybrid sol-gel route using boehmite sol as the precursor for alumina and titanium isopropoxide as the precursor for titania. The thermal properties, XRD phase analysis, specific surface area, adsorption isotherms and pore size details along with temperature programmed desorption of ammonia are presented. A specific surface area as high as 291 m(2)/g is observed for 1:5 Al(2)O(3)/TiO(2) composition calcined at 400 A degrees C, but the same composition when calcined at 1,000 A degrees C, resulted in a surface area of 4 m(2)/g, while 1:0.5 composition shows a specific surface area of 41 m(2)/g at 1,000 A degrees C. Temperature programmed desorption (of ammonia) results show more acidic nature for the titania rich mixed oxide compositions. Transmission electron microscopy of low and high titania content samples calcined at 400 A degrees C, shows homogeneous distribution of phases in the nano range. In the mixed oxide, the particle size ranges between 10-20 nm depending on titania content. The detailed porosity data analysis contributes very much in designing alumina-titania mixed oxide nanocatalysts