Platinum-dispersed carbon was prepared from amphiphilic carbonaceous material and [Pt(NH 3 ) 4 ](OH) 2 using ammonia water. These reaction mixtures gelled and were dried then finally heat-treated. In all the samples, platinum particle diameters varied from a few nanometers to 20 nm in the carbon matrix. The platinum-dispersed carbon that had only been heat-treated did not exhibit any catalytic activity for hydrogenation of cyclohexene. However, activation with CO 2 enhanced the catalytic activity, which depended on the activation time and on the Pt loading.