NOx storage capacity, SO2 resistance and regeneration of Pt/(Ba)/CeZr model catalysts for NOx-trap system.
Résumé
NOx storage capacity, sulphur resistance and regeneration of 1wt%Pt/Ce0.7Zr0.3O2 (Pt/CeZr) and 1wt%Pt /10wt%BaO /Ce0.7Zr0.3O2 (Pt/Ba/CeZr) catalysts were studied and compared to a 1wt%Pt/10wt%BaO/Al2O3 (Pt/Ba/Al) model catalyst submitted to the same treatments. Pt/Ba/CeZr presents the best NOx storage capacity at 400°C in accordance with basicity measurements by CO2 TPD and Pt/CeZr shows the better performance at 200°C mainly due to a low sensitivity to CO2 at this temperature. For all samples, sulphating induces a detrimental effect on NOx storage capacity but regeneration at 550°C under rich conditions generally leads to the total recovery of catalytic performance. However, the nearly complete sulphur elimination is only observed on Pt/CeZr. Moreover, an oxidizing treatment at 800°C leads to partial sulphates elimination on the Pt/CeZr catalyst whereas a stabilization of sulphates on Ba containing species is observed.
Domaines
Catalyse
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NSC, SO2 resistance and regeneration of Pt-(Ba)-CeZr for NOx-trap HAL.pdf (253.31 Ko)
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