NOx Adsorber Materials: Fundamental Studies, and Investigations of Sulfur Poisoning and Thermal Deactivation
EMSL Project ID
19800
Abstract
One of the key challenges facing the catalysis community is the elimination of harmful gases emitted by internal combustion engines. In particular, the reduction of NOx from an exhaust gas mixture that contains an excess amount of oxygen is difficult. Traditional three-way catalysts do not work under lean conditions because the concentrations of the reductants (CO and hydrocarbons) are greatly reduced by their oxidation with O2 on the noble metal components of these catalysts. Therefore, new approaches to NOx reduction have been considered in the last decade. In spite of all the efforts to develop new emission control technologies for lean NOx reduction, only limited applications have been achieved. One of the most promising technologies under consideration is the NOx adsorber catalyst (aka NOx storage/reduction, NSR, or Lean NOx Trap, LNT) method. This process is based on the ability of certain oxides, in particular alkaline and alkaline earth oxide materials, to store NOx under lean conditions and release it during rich (excess reductant) engine operation cycles. Since the original reports on this technology from Toyota in the mid `90s [1], the most extensively studied catalyst system continues to be based on barium oxide (BaO) supported a high surface area alumina (Al2O3) material [2]. Our program is aimed at developing a practically useful fundamental understanding of the operation of the LNT technology especially with respect to the optimum materials used in LNTs.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-07-21
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
167) Yi, C.-W.; Kwak, J.H.; Peden, C.H.F.; Wang, C.; Szanyi, J. "Understanding Practical Catalysts Using a Surface Science Approach: The Importance of a Strong Interaction between BaO and Al2O3 in NOx Storage Materials." J. Phys. Chem. C 111 (2007) 14942-14944.
173) Epling, W.S.; Peden, C.H.F.; Szanyi, J. "Carbonate Formation and Stability on a Pt/BaO/Al2O3 NOx Storage/Reduction Catalyst." J. Phys. Chem. C 112 (2008) 10952-10959.
178) Kim, D.H.; Kwak, J.H.; Wang, X.; Szanyi, J.; Peden, C.H.F. "The Roles of Pt and BaO in the Sulfation of Pt/BaO/Al2O3 Lean NOx Trap Materials: Sulfur K-Edge XANES and Pt LIII XAFS Studies." J. Phys. Chem. C 112 (2008) 2981-2987.
Cheng Y, J Hoard, C Lambert, JH Kwak, and CHF Peden. 2008. "NMR Studies of Cu/zeolite SCR Catalysts Hydrothermally Aged with Urea." Catalysis Today 136(1-2):34-39. doi:10.1016/j.cattod.2008.01.019
Disselkamp, R.S.; Tonkyn, R.G.; Chin, Y.-H.; Peden, C.H.F. "Developing Multiple-Site Kinetic Model in Catalysis Simulations: A Case Study of O2 + 2 NO ↔ 2 NO2 Oxidation-Reduction Chemistry on Pt(100) Catalyst Crystal Facets." J. Catal. 238 (2006) 1-5.
Epling WS, I Nova, and CHF Peden. 2008. "Preface." Catalysis Today 136(1-2):1-2. doi:10.1016/j.cattod.2008.03.008
Kim, D.H.; Chin, Y.-H.; Muntean, G.G.; Yezeretz, A.; Currier, N.C.; Epling, W.S.; Chen, H.-Y.; Hess, H.; Peden, C.H.F. "Design of a reaction protocol for de-coupling desulfation and thermal aging effects during regeneration of Pt-BaO/Al2O3 lean NOx trap catalysts." Ind. Eng. Chem. Res., 46 (2007) 2735-2740.
Kim, D.H.; Chin, Y.-H.; Muntean, G.G.; Yezeretz, A.; Currier, N.C.; Epling, W.S.; Chen, H. Y.; Hess, H.; Peden, C.H.F. "Relationship of Pt Particle Size with the NOx Storage Performance over Thermally Aged Pt/BaO/Al2O3 Lean NOx Trap Catalysts." Ind. Eng. Chem. Res. 45 (2006) 8815-8821.
Kim DH, JH Kwak, X Wang, J Szanyi, and CHF Peden. 2008. "Sequential high temperature reduction, low temperature hydrolysis for the regeneration of sulfated NOx trap catalysts." Catalysis Today 136(1-2):183-187. doi:doi:10.1016/j.cattod.2007.12.134
Kim, D.H.; Kwak, J.H.; Szanyi, J.; Burton, S.D.; Peden, C.H.F. "Water-induced Bulk Ba(NO3)2 Formation From NO2 Exposed Thermally Aged BaO/Al2O3." Appl. Catal. B 72 (2007) 233-239.
Kim, D.H.; Kwak, J.H.; Szanyi, J.; Wang, X.; Li, G.; Hanson, J.C.; Peden, C.H.F. "Characteristics of Desulfation Behavior for Presulfated Pt-BaO/CeO2 Lean NOx Trap Catalysts: The Role of the CeO2 Support." J. Phys. Chem. C 113 (2009) 21123-21129.
Kim, D.H.; Kwak, J.H.; Szanyi, J.; Wang, X.; Peden, C.H.F. "Promotional effects of CO2 on Desulfation Processes for Pre-Sulfated Pt-BaO/Al2O3 Lean NOx Trap Catalysts." Topics in Catal. 52 (2009) 1719-1722.
Kim, D.H.; Szanyi, J.; Kwak, J.H.; Szailer, T.; Hanson, J.C.; Wang, C.M.; Peden, C.H.F. "Effect of Barium Loading on the De-sulfation of Pt BaO/Al2O3 Studied by H2 TPRX, TEM, Sulfur K-edge XANES and In-situ TR-XRD." J. Phys. Chem. B 110 (2006) 10441-10448.
Kim, D.H.; Szanyi, J.; Kwak, J.H.; Wang, X.; Hanson, J.C.; Engelhard, M.; Peden, C.H.F. "Effects of Sulfation Level on the Desulfation Behavior of Pre-Sulfated Pt-BaO/Al2O3 Lean NOx Trap Catalysts: A Combined H2 TPRX, In-Situ Sulfur K-Edge XANES, XPS and TR-XRD Study." J. Phys. Chem. C 113 (2009) 7336-7341.
Kim DH, YH Chin, JH Kwak, and CHF Peden. 2008. "Promotional Effects of H2O Treatment on NOx Storage over Fresh and Thermally Aged Pt-BaO/Al2O3 Lean NOx Trap Catalysts ." Catalysis Letters 124(1-2):39-45. doi:10.1007/s10562-008-9505-6
Kwak JH, DH Kim, J Szanyi, and CHF Peden. 2008. "Excellent Sulfur Resistance of Pt/BaO/CeO2 Lean NOx Trap Catalysts." Applied Catalysis. B, Environmental 84(3-4):545-551. doi:10.1016/j.apcatb.2008.05.009
Kwak, J.H.; Hu, J.Z.; Kim, D.H.; Szanyi, J.; Peden, C.H.F. "Penta-coordinated Al3+ Ions as Preferential Nucleation Sites for BaO on γ-Al2O3: an Ultra-High Magnetic Field 27Al MAS NMR Study." J. Catal. 251 (2007) 189-194.
Kwak, J.H.; Kim, D.H.; Szanyi, J.; Szailer, T.; Peden, C.H.F. "NOx Uptake Mechanism on Pt/BaO/Al2O3 Catalysts." Catal. Lett. 111 (2006) 119-126.
Kwak, J.H.; Peden, C.H.F.; Szanyi, J. "Non-thermal plasma-assisted NOx reduction over Na-Y Zeolites: The promotional effect of acid sites." Catal. Lett. 109 (2006) 1-6.
Mei, D.; Ge, Q.; Kwak, J.H.; Kim, D.H.; Szanyi, J.; Peden, C.H.F. "Adsorption and Formation of BaO Overlayers on γ Al2O3 Surfaces." J. Phys. Chem. C 112 (2008) 18050 18060.
Mei, D.; Ge, Q.; Kwak, J.H.; Kim, D.H.; Verrier, C.; Szanyi, J.; Peden, C.H.F. "Characterization of Surface and Bulk Nitrates of γ-Al2O3?Supported Alkaline Earth Oxides using Density Functional Theory." Phys. Chem. Chem. Phys. 11 (2009) 3380-3389.
Mei, D.; Ge, Q.; Szanyi, J.; Peden, C.H.F. "A First-Principles Analysis of NOx Adsorption on Anhydrous γ-Al2O3 Surfaces." J. Phys. Chem. C 113 (2009) 7779-7789.
She, X.; Flytzani-Stephanopoulos, M.; Wang., C.; Wang, Y.; Peden, C.H.F. "SO2-induced stability of Ag-alumina catalysts in the SCR of NO with methane." Appl. Catal. B 88 (2009) 98-105.
Szailer, T.; Kwak, J.H.; Kim, D.H.; Hanson, J.; Peden, C.H.F.; Szanyi, J. "Reduction of Stored NOx on Pt/Al2O3 and Pt/BaO/Al2O3 Catalysts with H2 and CO." J. Catal. 239 (2006) 51-64.
Szanyi, J.; Kwak, J.H.; Chimentao, R.J.; Peden, C.H.F. "Effect of H2O on the adsorption of NO2 on γ-Al2O3: an in situ FTIR/MS study." J. Phys. Chem. C 111 (2007) 2661-2669.
Szanyi, J.; Kwak, J.H.; Kim, D.H.; Wang, X. Chimentao, R.J.; Hanson, J.C.; Epling, W.S.; Peden, C.H.F. "Water-Induced Morphology Changes in BaO/γ-Al2O3 NOx Storage Materials: an FTIR, TPD, and Time-Resolved Synchrotron XRD Study." J. Phys. Chem. C 111 (2007) 4678-4687.
Szanyi, J.; Kwak, J.H.; Kim, D.H.; Wang, X.; Hanson, J.C.; Chimentao, R.J.; Peden, C.H.F. "Water-Induced Morphology Changes in BaO/γ-Al2O3 NOx storage materials." Chem. Comm. (2007) 984-986.
Tonkyn, R.G.; Disselkamp, R.S.; Peden, C.H.F. "Nitrogen Release from a NOx Storage and Reduction Catalyst." Catal. Today 114 (2006) 94-101.
Understanding the nature of surface nitrates in BaO/γ-Al2O3 NOx storage materials: A combined experimental and theoretical study
Ja Hun Kwak a, Donghai Mei a,∗, Cheol-Woo Yi a,1, Do Heui Kima, Charles H.F. Peden a, Lawrence F. Allard b,
János Szanyi a,∗
a Institute for Interfacial Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-80, Richland, WA 99352, USA
b High Temperature Materials Laboratory, Oak Ridge National Laboratory, TN, USA
Journal of Catalysis 261 (2009) 17-22.
Verrier CLM, JH Kwak, DH Kim, CHF Peden, and J Szanyi. 2008. "NOx uptake on alkaline earth oxides (BaO, MgO, CaO and SrO) supported on γ-Al2O3." Catalysis Today 136(1-2):121-127. doi:doi:10.1016/j.cattod.2007.12.138