Sol-gel synthesis of alumina, titania and mixed alumina/titania in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulphonyl) amide

In this paper we report on the synthesis of alumina, titania and mixed alumina-titania in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulphonyl) amide [Py-1,Py-4]TFSA via sol-gel methods using aluminium isopropoxide and titanium isopropoxide as precursors. Our results show that the as-synthesized alumina is mainly mesoporous boehmite with an average pore diameter of 3.8 nm. The obtained boehmite is subject to a phase transformation into gamma-Al2O3 and delta-Al2O3 after calcinations at 800 and 1,000 A degrees C, respectively. The as-synthesized TiO2 shows amorphous behaviour and calcination at 400 A degrees C yields anatase which undergoes a further transformation to rutile at 800 A degrees C. The as-prepared alumina-titania powders are amorphous and transformed to rutile and alpha-Al2O3 after calcination at 1,000 A degrees C TiO2. The obtained alumina-titania has a higher surface area than those of alumina or titania. The surface area of the as-synthesized alumina-titania was found to exceed 486 m(2) g(-1), whereas the surface areas of the as-synthesized boehmite and titania were around 100 m(2) g(-1), respectively.