Article Dans Une Revue Studies in Surface Science and Catalysis Année : 1995

Reactivity of steam in exhaust gas catalysis. part II: Sintering and regeneration of Rh and PtRh catalysts in propane oxidation

Résumé

PtRh catalysts were prepared on different supports composed of Al2O3, CeO2, ZrO2 and NiAl2O4. The variations of the activities in propane oxidation and steam reforming were used to obtain some indication concerning the surface state of these catalysts after thermal treatments at high temperature in an oxidizing and in a reducing medium. Cyclopentane hydrogeonolysis was also carried out to observe the changes in the rhodium surface state. Platinum was the metal which catalysed the direct oxidation of propane while rhodium was the key-component in steam reforming catalysis. The treatment at 800°C in an oxidizing medium induces a very important decrease of Rh area linked to the fact that rhodium in its oxidized form (Rh3+) can diffuse into the support. This phenomenon is more marked on Al2O3 and, to a lesser extent on CeO2-Al2O3, than on the other supports. On the other hand, oxidative treatments lead to an increase of the particle size of platinum, and temporarily to an enhancement of the oxidation activities. After a treatment in a reducing medium at high temperature (T>700°C), the steam reforming activities can be recorved by extraction of rhodium from the support, with two exceptions however: Rh/CeO2-Al2O3 and PtRh/ZrO2 catalysts. This treatment has pratically no impact on platinum activities in oxidation except for the catalysts supported on NiAl2O4 which are deactived. Cyclopentane hydrogenolysis confirm all the above results.

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hal-04999137 , version 1 (20-03-2025)

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Jacques Barbier Jr., Daniel Duprez. Reactivity of steam in exhaust gas catalysis. part II: Sintering and regeneration of Rh and PtRh catalysts in propane oxidation. Studies in Surface Science and Catalysis, 1995, Studies in Surface Science and Catalysis, 96, pp.73-84. ⟨10.1016/S0167-2991(06)81420-5⟩. ⟨hal-04999137⟩

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