Effects of Hydrothermal Aging on the Performance of Four Different Formulations of Three way Catalyst in Exhaust Conditions Relevant to Propane Engines

Daekun  Kim, University of Tennessee

Daekun Kim^a,*, Todd J. Toops^b, Ke Nguyen^a, Pranaw Kunal^b

^a University of Tennessee, Knoxville, TN 37996, United States

^b Oak Ridge National Laboratories, Oak Ridge, TN 37831, United States

* – presenting author

The effects of hydrothermal aging on the performance of four different formulations of a family of prototype three-way catalyst samples were investigated in a bench-flow reactor using simulated exhaust gases with C₃H₈ as the only hydrocarbon component. The formulations differ in the loading of Pd/Rh and the amount of the oxygen storage material. All TWC samples were aged at 820°C for 50h, followed by further aging at 900°C for 50h under prescribed US-DRIVE aging conditions. The degradation in the performance of the hydrothermal-aged TWC samples was investigated using T50 and T90 for NO, CO and C₃H₈, water-gas-shift (WGS) reaction, steam reforming (SR) reaction, and oxygen storage capacity (OSC).  Results indicate that the performance of TWC formulation with the only Pd at a loading of 6.5 g/L and a high amount of oxygen storage material is the least degraded from the hydrothermal aging. On the other hand, the performance is the most degraded for the bimetallic formulation without OSC with a loading of Pd and Rh of 6.36 g/L and 0.14 g/L, respectively. In addition, N₂ physisorption analysis was performed on fresh and hydrothermally aged TWC samples from which the effects of aging on the surface area, pore-volume, and pore size distribution are characterized.

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