Skip to main content

Fundamental Studies of Vehicle Emission Control Catalysts

EMSL Project ID


The abatement of environmentally harmful NOx compounds (NO, NO2, and N2O) emitted from mobile or stationary power sources remains a challenging task for the catalysis community. In particular, conventional three-way catalysts used in the exhaust after treatment technologies of internal combustion engines prove ineffective when the engine is operated under highly oxidizing conditions (to achieve better fuel efficiency). The problem is daunting, since reduction chemistry (NOx to N2) has to be carried out under highly oxidizing conditions. Several approaches have been proposed for lean-NOx abatement, each of them with its own specific sets of problems. The two technologies that seem to have clear advantages among the processes proposed are the selective catalytic reduction either with hydrocarbons (HC-SCR) or with ammonia (NH3-SCR), and NOx storage reduction (NSR). For the NH3-SCR technology, transition metal (in particular Fe and Cu) ion-exchanged zeolite catalysts have shown high activity and N2 selectivity. NSR catalysts work under cyclic operation conditions: oxidation of NO to NO2 followed by storage as nitrates/nitrites on alkali or alkaline oxides under lean conditions, and subsequent reduction of the released NOx under rich conditions. To further advance these important exhaust emission technologies, we are carrying out several research programs, funded by DOE/Office of Energy Efficiency and Renewable Energy (EERE)/Vehicle Technologies Program (VT), involving both programs that include direct collaboration with industry partners (at GM, Ford and Cummins), and a more fundamental program. For all of these programs, we rely on the use of a wide array of state-of-the-art catalyst characterization facilities in the EMSL at PNNL.

Project Details

Start Date
End Date


Principal Investigator

Charles Peden
Pacific Northwest National Laboratory


Ja Hun Kwak
Ulsan National Institute of Science and Technology

Team Members

Renqin Zhang
University of Texas at Austin

Feng Gao
Pacific Northwest National Laboratory

Marton Kollar
Pacific Northwest National Laboratory

Donghai Mei
Tiangong University

Janos Szanyi
Pacific Northwest National Laboratory

Related Publications

Beale A M,Gao F ,Lezcano-Gonzalez I ,Peden C HF,Szanyi J 2015. "Recent advances in automotive catalysis for NOx emission control by small-pore microporous materials" Chemical Society Reviews 44(20):7371-7405. 10.1039/c5cs00108k
Gao F, Y Wang, M Kollár, NM Washton, J Szanyi, and CHF Peden. "A comparative kinetics study between Cu/SSZ-13 and Fe/SSZ-13 SCR catalysts." Catalysis Today. doi:10.1016/j.cattod.2015.01.025
Kim DH, KK Mudiyanselage, J Szanyi, JC Hanson, and CHF Peden. 2014. "Effect of H2O on the morphological changes of KNO3 formed on K2O/Al2O3 NOx storage materials: Fourier transform infra-red (FTIR) and time-resolved x-ray diffraction (TR-XRD) studies." Journal of Physical Chemistry C 118(8):4189–4197. doi:10.1021/jp410816r
Kwak JH, JH Lee, SD Burton, AS Lipton, CHF Peden, and J Szanyi. 2013. "A common intermediate for N2 formation in enzymes and zeolites: side-on Cu-nitrosyl complexes." Angewandte Chemie International Edition 52(38):9985-9989. doi:10.1002/anie.201303498
Righini L, F Gao, L Lietti, J Szanyi, and CHF Peden. 2016. "Performance and Properties of K and TiO2 Based LNT Catalysts." Applied Catalysis. B, Environmental 181:862–873. doi:10.1016/j.apcatb.2015.07.008
Righini L, F Gao, L Lietti, J Szanyi, and CHF Peden. "Performance and Properties of K and TiO2 Based LNT Catalysts." Applied Catalysis B: Environmental. doi:10.1016/j.apcatb.2015.07.008