Insights into NO Adsorption and Desorption phenomena on Pd-Exchanged Zeolite Passive NOx Adsorbers

Sreshtha  Sinha Majumdar, Oak Ridge National Laboratory

Insights into NO Adsorption and Desorption phenomena on Pd-Exchanged Zeolite Passive NOx Adsorbers

Sreshtha Sinha Majumdar1, Josh Pihl1, Kevin Gu2, William Epling2

1National Transportation Research Center, Oak Ridge National Laboratory

2 University of Virginia

 

 

Improved combustion efficiency of engines will drive the exhaust to lower temperatures resulting in challenges associated with low-temperature emissions control. The U.S. DRIVE government/industry partnership has presented a target to develop catalytic materials that can convert 90% emissions at 150 °C in response to the challenges associated with low-temperature emissions control. Trap materials such as passive NOx adsorbers (PNA) and hydrocarbon traps could play a critical role in meeting the emissions regulations for high efficiency advanced combustion engines by trapping the regulated pollutants at low temperatures and releasing them at temperatures higher than the catalyst light-off temperature. Capturing the storage and release processes will enable accurate modelling of these materials. The results from our investigations into model PNAs by combining flow-reactor experiments with DRIFTS (Diffuse Reflectance Infra-red Fourier Transform Spectroscopy) to gain insights into possible mechanisms for NO storage and release on Pd-exchanged zeolite PNAs will be presented.