Understanding ammonia and nitrous oxide formation in typical three-way catalysis during the catalyst warm-up period.

Ammonia (NH) and nitrous oxide (NO) have been regarded as the typical secondary pollutants emitted from vehicles equipped with a three-way catalyst (TWC). MultiGas FT-IR Analyzer was applied to determine the outlet gas concentrations in the light-off experiments, in order to understand how different reaction conditions and catalyst aging affect the production of these two pollutants. It was found that NO formation is favored by the existence of excess oxygen during NO reduction, whereas NH is readily formed within the lack of reactive oxygen species.