Macro- and Microkinetic Simulation of Diesel Oxidation Catalyst: Effect of Aging, Noble Metal Loading and Platinum Oxidation

In automotive exhaust aftertreatment simulation, both macro- and microkinetic models are commonly used. In this contribution both models are applied for the simulation of diesel oxidation catalysts (Pt/-Al2O3) with different catalyst loading and degree of thermal aging. The study proves that the structure insensitive kinetics of the considered catalysts can be described with the same rate equations only by scaling the rate constants of the different reaction steps with the catalytically active Pt surface, which is accessible by CO adsorption or light-off measurements. In addition, NO oxidation is strongly influenced by a reversible, slow transformation of Pt into Pt-oxide.