Cobalt/aluminium mixed oxides of varying compositions (0.05 to 0.2 C0304:A120J) were prepared by impregnating finelly powdered poorly crystalline gama-alumina with different propor­tions of cobalt nitrate using a pore-filling method. The prepared solids were dried ilt 100°C then cal­cined at 450-900°C. The catalytic activities of different supported solids were determined using the catalytic oxidation of CO with 02 at 80- 300°C by these mixed oxides. The apparrent activation ener­gies (D-E) of the catalytic reaction were determined for each catalyst from the data of first-order reac­tion rate constant (k) measured at different reaction temperatures for various solids precalcined at different temperatures.The results obtained revealed that the catalytic activity increases progressively by increasing the amount of cobalt o

G A EL SHOBAKY ,G A FAGAL ,NABIL H AMIN ,