Alumina has been extensively used as a catalyst support material. It exists in several different phases namely y, r], 8,0 and a. Phase transformations (eg y -» 8 0 —> a) can occur at well defined temperatures. If transformations occur during catalyst use, then the activity of the catalyst can be reduced significantly. In this project, the effect of addition of metals to ti-A120 3 was investigated in an effort to stablise the high surface area phase at high temperatures. The following ions were added at 1 and 3wt% loadings’ Ba2+, Ca2+, Ce3+, Cs+, La3+ and Zr4*. In this investigation the order of the T|-A120 3 stablisation at 1270K was found to be as follows: La3+ > Ce3+ = Cs+ > Zr4* « Ba2+ - Ca2+ Chemisorption measurements on Pt/n-Al20 3 catalysts, showed that the maximum dispersion of platinum (Pt) was obtained at a 3wt% loading. Catalyst samples containing this loading of Pt on tj-A120 3 were then prepared with the incorporation of either of the ions, La3+, Ce3+, Cs+ and Sn4+ The method of preparation of these samples was vaned by using either co-impregriation or step impregnation and the activity of the resulting catalysts was tested using the reaciton, iso - C4 H10 + 0 2 ------> PRODUCTS the most active catalyst sample was found to be lwt%Cs, 3wt%Pt/n-Al20 3, having a catalytic activity of up to 10 times greater than a 3wt% Pt/n-Al20 3.