Pt-Sn/gamma-Al2O3 catalysts with different Sn loadings were prepared by incipient wetness coimpregnation of gamma-Al2O3 with H2PtCl6 and SnCl2. The Pt-Sn interaction was tested by temperature-programmed reduction and the catalytic activity was measured by cyclohexane dehydrogenation. The catalysts were coked by cyclopentane at 500 degreesC and totally or partially decoked with O-2 at 450 degreesC or O-3 at 125 degreesC. Coke deposits were studied by TPO and the catalytic activity of coked catalysts, partially or totally regenerated, by cyclohexane dehydrogenation. The TPO with O-3 shows that coke combustion with O-3 starts at a low temperature and has a maximum at 150degreesC, that is a compensation between the increase of the burning rate and the rate Of O-3 decomposition when increasing the temperature. Meanwhile O-2 burns coke with a maximum at 500degreesC. When performing partial decoking with O-3 (125 degreesC) the remaining coke is more oxygenated and easier to burn than the coke that remains after decoking with O-2 (450 degreesC). After burning with 03 the dehydrogenation activity of the fresh catalyst is recovered, while after burning with 02 the activity is higher than that of the fresh catalyst. The burning with 03 Practically does not change the original Pt-Sn interaction while the burning with 02 produces a decrease in the interaction, producing free Pt sites with higher dehydrogenation capacity. The differences in coke combustion with O-3 and O-2 are due to the different form of generation of activated oxygen, the species that oxidizes the coke. O-3 is activated by the gamma-Al2O3 support at low temperatures firstly eliminating coke from the support while O-2 is activated by Pt at temperatures higher than 450 degreesC and the coke removal starts on the metal. Then, the recovery of the Pt catalytic activity as a function of coke elimination is faster with O-2 than with O-3. (C) 2004 Elsevier B.V. All rights reserved.