Reduction of NOx stored at low temperatures on a NOx adsorbing catalyst

Isothermal storage and reduction of NO2 with CO, C3H6 and H2 as reducing agents on a lean NOx adsorber was investigated by temperature programmed desorption (TPD) and temperature programmed reduction (TPR) studies. The reduction of NOx was clearly favoured with H2 as reducing agent. Carbon monoxide and C3H6 showed fairly low reduction of NOx. The NOx reduction at low temperatures with H2 as reducing agent was found to be effective, clearly much more effective than for CO.