Ammonia is a byproduct during NOx reduction over TWC catalysts dedicated for stoichiometric CNG vehicles, which has been proposed a mass-per-distance limit for Euro 7 legislation. Temperature-programmed reaction under a simulated pollutant emission has revealed an increasing level of ammonia formation with longer hydrothermally aging time for the CNG-dedicated TWC catalyst which is composed of noble metals (Pt, Pd, Rh), La-Al2O3 support and CeZr materials. By monitoring the emissions of ammonia over mono-component supported catalysts, it's confirmed that ammonia is derived from NO reduction by H2 over the aged Pt/La-Al2O3 catalyst. Correlation between the selectivity of ammonia and the diameter of Pt nanoparticles demonstrates the formation of ammonia is induced by Pt aggregation.

What contributes to the formation of ammonia over CNG vehicle-dedicated catalysts?

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.