Understanding NOx SCR Mechanisms and Activity on Cu/Chabazite Structures throughout the Catalyst Life Cycle
EMSL Project ID
47953
Abstract
This proposed EMSL use will enable research that has been recently funded at PNNL by the Department of Energy (DOE), and at the remainder of the partner institutions by a joint DOE/National Science Foundation (NSF) program. For this recently funded research, the PIs provide a team with a wealth of experience in both the application and science of heterogeneous catalysis, especially as related to NOx chemistry, and with outstanding expertise in the diverse tools necessary to achieve the objectives of the proposed studies.The selective catalytic reduction (SCR) with ammonia on Cu- and Fe-exchanged chabazite (CHA) zeolites is the state-of-the-art for lean NOx reduction in excess oxygen and thus enables access to the fuel efficiency of lean burn engines. Although these materials are used commercially, their structure and catalytic behavior changes in unpredictable ways as they respond to varying SCR reaction conditions and in particular as they accumulate sulfur species that cause deactivation. To dramatically improve today's materials, to optimize engine efficiency within emission constraints, and to circumvent deactivation, a microscopically detailed model of catalyst performance under all operating conditions and through the life cycle is essential.
Cu/CHA and Fe/CHA catalysts present multiple and dynamic active site functionalities that contribute to overall activity and deactivation. Our synthetic capability to vary framework Al density and influence Cu and Fe distributions between the six- and eight-ring structures in CHA, to prepare zeolites with similar six- and eight-ring structures, and to widely vary Al, Fe and Cu content will provide a set of materials that emphasize specific local active site structures for comparison. Detailed kinetic analysis and unique operando characterization of the Cu and Fe will be obtained using EMSL EPR and Mossbauer spectrometers, and with synchrotron x-ray absorption spectroscopy (XAS) at another DOE user facility, the Advanced Photon Source at Argonne National Laboratory. A critical characterization tool will be with solid-state NMR which will be especially useful for characterizing Al distributions in the synthesized zeolites. Instrumentation in EMSL and in some of the PI's home laboratories will be used to obtain information on kinetically important intermediates with FTIR and isotopic switching, using methods developed by members of this team. DFT models will be implemented on the EMSL supercomputer to determine the structure, spectroscopies, and thermodynamic stability of candidate sites vs. local structure, and to identify reaction intermediates, steps and rates. As relationships between structure and catalytic behavior are identified, they will be used to set synthetic targets for new materials with active site distributions that optimize catalytic performance and robustness. Thus, our proposed approach brings to bear the full arsenal of modern catalysis science techniques, including a number of methods uniquely available to the catalysis science community via the EMSL user facility, to bear on a problem of great societal importance.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2013-10-01
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Chen H., M. Kollar, Z. Wei, F. Gao, Y. Wang, J. Szanyi, and C. Peden. 2019. "Formation of NO+ and its possible roles during the selective catalytic reduction of NOx with NH3 on Cu-CHA catalysts." Catalysis Today 320. PNNL-SA-129558. doi:10.1016/j.cattod.2017.12.022
Chen H-Y, Z Wei, M Kollar, F Gao, Y Wang, J Szanyi, and CHF Peden. 2015. "A comparative study of N2O formation during the selective catalytic reduction of NOx with NH3 on zeolite supported Cu catalysts." Journal of Catalysis 329:490-498. doi:10.1016/j.jcat.2015.06.016 (September 2015)
Chen HY, Z Wei, M Kollar, F Gao, Y Wang, J Szanyi, and CHF Peden. 2016. "NO oxidation on Zeolite Supported Cu Catalysts: Formation and Reactivity of Surface Nitrates." Catalysis Today 267:17-27. doi:10. 1016/j. cattod. 2015. 11. 039
Gao F, D Mei, Y Wang, J Szanyi, and CHF Peden. 2017. "Selective Catalytic Reduction over Cu/SSZ-13: Linking Homo- and Heterogeneous Catalysis." Journal of the American Chemical Society 139(13):4935-4942. doi:10.1021/jacs.7b01128
Gao F, ED Walter, M Kollar, Y Wang, J Szanyi, and CHF Peden. 2014. "Understanding ammonia selective catalytic reduction kinetics over Cu-SSZ-13 from motion of the Cu ions." Journal of Catalysis 319:1-14. doi:10.1016/j.jcat.2014.08.010
Gao F, ED Walter, NM Washton, J Szanyi, and CHF Peden. 2014. "Synthesis and Evaluation of Cu-SAPO-34 Catalysts for NH3-SCR. 2: Solid-state Ion Exchange and One-pot Synthesis." Applied Catalysis. B, Environmental 162:501-514. doi:10.1016/j.apcatb.2014.07.029
Gao F, ED Walter, NM Washton, J Szanyi, and CHF Peden. 2015. "Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis." Applied Catalysis. B, Environmental 162:501-514. doi:10.1016/j.apcatb.2014.07.029
Gao F, M Kollar, RK Kukkadapu, NM Washton, Y Wang, J Szanyi, and CHF Peden. 2015. "Fe/SSZ-13 as an NH3-SCR Catalyst: A Reaction Kinetics and FTIR/Mössbauer Spectroscopic Study." Applied Catalysis. B, Environmental 164:407-419. doi:10.1016/j.apcatb.2014.09.031
Gao F, NM Washton, Y Wang, M Kollar, J Szanyi, and CHF Peden. 2015. "Effects of Si/Al Ratio on Cu/SSZ-13 NH3-SCR Catalysts: Implications for the active Cu species and the Roles of Brønsted Acidity ." Journal of Catalysis 331:25–38. doi:10.1016/j.jcat.2015.08.004
Kovarik L, NM Washton, RK Kukkadapu, A Devaraj, A Wang, Y Wang, J Szanyi, CHF Peden, and F Gao. 2017. "Transformation of active sites in Fe/SSZ-13 SCR catalysts during hydrothermal aging: a spectroscopic, microscopic and kinetics study." ACS Catalysis 7(4):2458-2470. doi:10.1021/acscatal.6b03679
Kwak JH, T Varga, CHF Peden, F Gao, JC Hanson, and J Szanyi. 2014. "Following the movement of Cu ions in a SSZ-13 zeolite during dehydration, reduction and adsorption: a combined in situ TP-XRD, XANES/DRIFTS study." Journal of Catalysis 314(1):83-93. doi:10.1016/j.jcat.2014.03.003
Lim TH, SJ Cho, HS Yang, MH Engelhard, and DH Kim. 2015. "Effect of Co/Ni ratios in cobalt nickel mixed oxide catalysts on methane combustion." Applied Catalysis. A, General 505:62-69. doi:10.1016/j.apcata.2015.07.040
Li S, Y Zheng, F Gao, J Szanyi, and WF Schneider. 2017. "Experimental and Computational Interrogation of Fast SCR Mechanism and Active Sites on H-form SSZ-13." ACS Catalysis 7(8):5087–5096. doi:10.1021/acscatal.7b01319
Luo J, F Gao, AM Karim, P Xu, ND Browning, and CHF Peden. 2015. "Advantages of MgAlOx over ?-Al2O3 as a Support Material for Potassium-Based High Temperature Lean NOx Traps." ACS Catalysis. doi:10.1021/acscatal.5b00542
Luo J, F Gao, K Kamasamudram, N Currier, CHF Peden, and A Yezerets. 2017. "New insights into Cu/SSZ-13 SCR catalyst acidity. Part I: Nature of acidic sites probed by NH3 titration." Journal of Catalysis 348:291–299. doi:10.1016/j.jcat.2017.02.025
Paolucci C, AA Verma, SA Bates, VF Kispersky, JT Miller, R Gounder, N Delgass, F Ribeiro, and WF Schneider. 2014. "Isolation of the Copper Redox Steps in the Standard Selective Catalytic Reduction on Cu-SSZ-13." Angewandte Chemie International Edition 53(44):11828–11833. doi:10.1002/anie.201407030
Prodinger S, MA Derewinski, Y Wang, NM Washton, ED Walter, J Szanyi, F Gao, Y Wang, and CHF Peden. 2017. "Sub-micron Cu/SSZ-13: synthesis and application as selective catalytic reduction (SCR) catalysts." Applied Catalysis. B, Environmental 201:461-469. doi:10.1016/j.apcatb.2016.08.053
Song J., Y. Wang, E.D. Walter, N.M. Washton, D. Mei, L. Kovarik, and M.H. Engelhard, et al. 2017. "Towards rational design of Cu/SSZ-13 selective catalytic reduction catalysts: Implications from atomic-level understanding of hydrothermal stability." ACS Catalysis 7, no. 12:8214-8227. PNNL-SA-128659. doi:10.1021/acscatal.7b03020
Wang A, Y Guo, F Gao, and CHF Peden. 2017. "Ambient-temperature NO oxidation over amorphous CrOx-ZrO2 mixed oxide catalysts: Significant promoting effect of ZrO2." Applied Catalysis B 202:706–714. doi:10.1016/j.apcatb.2016.02.045
Wang A., Y. Wang, E.D. Walter, N.M. Washton, Y. Guo, G. Lu, and C. Peden, et al. 2019. "NH3-SCR on Cu, Fe and Cu+Fe exchanged Beta and SSZ-13 catalysts: hydrothermal aging and propylene poisoning effects." Catalysis Today 320. PNNL-SA-128427. doi:10.1016/j.cattod.2017.09.061
Wang A, Y Wang, ED Walter, RK Kukkadapu, Y Guo, G Lu, RS Weber, Y Wang, CHF Peden, and F Gao. 2018. "Catalytic N2O decomposition and reduction by NH3 over Fe/Beta and Fe/SSZ-13 catalysts." Journal of Catalysis 358:199-210. doi:10.1016/j.jcat.2017.12.011
Wang D, F Gao, CHF Peden, J Li, K Kamasamudram, and WS Epling. 2014. "Selective catalytic reduction of NOx with NH3 over a Cu-SSZ-13 catalyst prepared by a solid state ion exchange method." ChemCatChem 6(6):1579-1583. doi:10.1002/cctc.201402010
Zhang R, JS McEwen, M Kollar, F Gao, Y Wang, J Szanyi, and CHF Peden. 2014. "NO Chemisorption on Cu/SSZ-13: a Comparative Study from Infrared Spectroscopy and DFT Calculations." ACS Catalysis 4(11):4093?4105. doi:10.1021/cs500563s
Zheng Y, L Kovarik, MH Engelhard, Y Wang, Y Wang, F Gao, and J Szanyi. 2017. "Low-Temperature Pd/Zeolite Passive NOx Adsorbers: Structure, Performance and Adsorption Chemistry." Journal of Physical Chemistry C 121(29):15793-15803. doi:10.1021/acs.jpcc.7b04312