Preparation of xTiO(2)center dot(1-x)Al2O3 catalytic supports by the sol-gel method: physical and structural characterisation

A series of xTiO(2).(1 - x)Al2O3 mixed oxides has been prepared by the sol- gel method with variable amounts of TiO2, from pure alumina to pure titania . Textural, bulk and surface characterisation of the samples has been carri ed out by nitrogen physisorption (S-BET, porosity), thermal analysis (TGA, DTA), X-ray diffraction (XRD), zero point charge (ZPC) and surface acidity. The textural results show that at low titania contents, higher surface are as than those of pure alumina are obtained, and in the titania-rich samples , higher surface areas than for pure titania are stabilised. The titanium c ontent also affects the crystallization process. Furthermore, the strength and distribution of the acid sites may be varied by changing the compositio n of the mixed oxide. (C) 2000 Kluwer Academic Publishers.