Kinetic modelling of Pt and Pt:Pd diesel oxidation catalysts

• Kinetic models for the reactions over Diesel oxidation catalysts.
• The production of N2O is included in the model.
• Global models based on extensions to LHHW type formulations are proposed.
• The models exhibit a good predictive ability.

This paper describes an experimental and theoretical investigation of the oxidation of carbon monoxide, nitrogen monoxide and propene, and the reduction of nitrogen monoxide by propene over two diesel oxidation catalysts. Synthetic exhaust gas mixtures are used. The catalysts were commercial monolith samples of 400 CPSI with a total PGM loading of 95 g/ft3. One monolith had platinum catalyst only, and the other was a bimetallic catalyst of 4:1 by mass platinum and palladium. The bimetallic catalyst was more active, and showed a different behaviour for propene oxidation than the Pt only catalyst. Global kinetic models for the oxidation of CO, C3H6, and NO, and the selective catalytic reduction of NO to N2 and N2O are developed. A good agreement between experimental results and simulation is observed.

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