The effect of the incorporation of a metallic phase (Pt) into a superacid catalyst (SO 2− 4 –ZrO 2 ) for n-butane isomerization was studied. The convenience of supporting Pt directly on the superacid or on alumina and of using the physical mixture as a catalyst was also analyzed. Pt supported on SO 2− 4 –ZrO 2 has the same activity as SO 2− 4 –ZrO 2 , but the stability is increased. The bifunctional reaction mechanism is not operating because Pt does not have metallic properties due to a strong interaction with the support under the experimental conditions of reduction (573 K). When Pt is supported on Al 2 O 3 and mixed mechanically with SO 2− 4 –ZrO 2 , the activity and stability are increased due to the operation of the bifunctional mechanism.