Topics in Catalysis

, Volume 60, Issue 3–5, pp 243–249 | Cite as

Microwave Cavity Perturbation Studies on H-form and Cu Ion-Exchanged SCR Catalyst Materials: Correlation of Ammonia Storage and Dielectric Properties

  • D. Rauch
  • M. Dietrich
  • T. Simons
  • U. Simon
  • A. Porch
  • R. Moos
Original Paper


Ammonia-based selective catalytic reduction (SCR) has become the major control strategy for NOx emissions from light and heavy duty diesel engines. Before reducing NOx on the SCR active material, ammonia storage on the active sites of the catalyst is crucial. The in operando measurement of the dielectric properties of the catalyst material using microwave cavity perturbation is a promising indicator of ammonia loading. In this work, the influence of copper ion-exchange of the zeolite-based SCR material ZSM-5 on the NH3 storage and the dielectric properties is highlighted. The catalyst powder samples were monitored by microwave cavity perturbation as a function of the stored ammonia content at a frequency of approximately 1.2 GHz in a temperature range between 200 and 350 °C. Due to ion exchange, the NH3 storage behavior changes, what could be monitored in the sensitivity of the dielectric permittivity to NH3. The dependence of the complex dielectric permittivity on ammonia loading is decreased by ion exchange, hinting that mostly ammonia storage on Brønsted sites affects the dielectric permittivity. This finding adds new knowledge to the electrical conduction and polarization mechanisms occurring in these zeolite materials.


NH3 storage Microwaves Cavity perturbation Zeolites ZSM-5 



R.M. is indebted to the German Research Foundation (DFG) for supporting this work under grant MO 1060/19-1.U.S. acknowledges financial supported by the German Research Foundation (DFG), contract No: Si609/14-1, and by the Exploratory Research Space of RWTH Aachen University within the Center for Automotive Catalytic Systems Aachen (ACA).A.P. acknowledges the support of Merck GKaA.


  1. 1.
    Johnson TV (2009) Review of diesel emission and control. Int J Engine Res. doi: 10.1243/14680874jer04009 Google Scholar
  2. 2.
    Rahkamma-Tolonen K, Maunula T, Lomma M, Huuhtanen M, Keiski RL (2005) The effect of NO2 on the activity of fresh and aged zeolite catalysts in the NH3-SCR reaction. Catal Today. doi: 10.1016/j.cattod.2004.09.056 Google Scholar
  3. 3.
    Di Iorio JR, Ribeiro FH, Bates SA, Verma AA, Miller JT, Gounder R (2015) The dynamic nature of Brønsted acid sites in Cu–Zeolites during NOx selective catalytic reduction: quantification by gas-phase ammonia titration. Top Catal. doi: 10.1007/s11244-015-0387-8 Google Scholar
  4. 4.
    Gao F, Wang Y, Kollár M, Washton NM, Szanyi J, Peden CHF (2015) A comparative kinetics study between Cu/SSZ-13 and Fe/SSZ-13 SCR catalysts. Catal Today. doi: 10.1016/j.cattod.2015.01.025 Google Scholar
  5. 5.
    Koebel M, Elsener M, Kleemann M (2000) Urea-SCR: a promising technique to reduce NOx emissions from automotive diesel engines. Catal Today. doi: 10.1016/s0920-5861(00)00299-6 Google Scholar
  6. 6.
    Rodriguez-Gonzalez L, Rodriguez-Castellon E, Jimenez-Lopez A, Simon U (2008) Correlation of TPD and impedance measurements on the desorption of NH3 from zeolite H-ZSM-5. Solid State Ion. doi: 10.1016/j.ssi.2008.06.007 Google Scholar
  7. 7.
    Giodanino F, Borfecchia E, Lomachenko K, Lazzarini A, Agostini G, Gallo E, Soldatov AV, Beato P, Bordiga S, Lamberti C (2014) Interaction of NH3 with Cu-SSZ-13 catalyst: a complementary FTIR, XANES, and XES study. J Phys Chem Lett. doi: 10.1021/jz500241m Google Scholar
  8. 8.
    Franke M, Simon U (2004) Solvate-supported proton transport in Zeolites. ChemPhysChem. doi: 10.1002/cphc.200301011 Google Scholar
  9. 9.
    Niwa M, Katada N (2013) New method for the temperature-programmed desorption (TPD) of ammonia experiment for characterization of zeolite acidity: a review. Chem Record. doi: 10.1002/tcr.201300009 Google Scholar
  10. 10.
    Janssens TVW, Falsig H, Lundegaard LF, Vennestrøm PNR, Rasmussen SB, Moses PG, Giordanino F, Borfecchia E, Lomachenko KA, Lamberti C, Bordiga S, Godiksen A, Mossin S, Beato P (2015) A consistent reaction scheme for the selective catalytic reduction of nitrogen oxides with ammonia. ACS Catal. doi: 10.1021/cs501673g Google Scholar
  11. 11.
    Moos R, Beulertz G, Reiß S, Hagen G, Votsmeier M, Fischerauer G, Gieshoff J (2013) Overview of the microwave-based automotive catalyst state diagnosis. Top Catal. doi: 10.1007/s11244-013-9980-x Google Scholar
  12. 12.
    Moos R, Wedemann M, Spörl M, Reiß S, Fischerauer G (2009) Direct catalyst monitoring by electrical means: an overview on promising novel Principles. Top Catal. doi: 10.1007/s11244-009-9399-6 Google Scholar
  13. 13.
    Beulertz G, Herbst F, Hagen G, Fritsch M, Gieshoff J, Moos R (2013) Microwave cavity perturbation as a tool for laboratory in situ measurements of the oxidation state of three way catalysts. Top Catal. doi: 10.1007/s11244-013-9987-3 Google Scholar
  14. 14.
    Reiß S, Wedemann M, Spörl M, Fischerauer G, Moos R (2011) Effects of H2O, CO2, CO, and flow rates on the RF-based monitoring of three-way catalysts. Sens Lett. doi: 10.1166/sl.2011.1472 Google Scholar
  15. 15.
    Sappok A, Parks J, Prikhodko V (2010) Loading and regeneration analysis of a diesel particulate filter with a radio frequency-based sensor. SAE Technical Paper. doi: 10.4271/2010-01-2126 Google Scholar
  16. 16.
    Feulner M, Hagen G, Moos R, Piontkowski A, Müller A, Fischerauer G, Brüggemann D (2013) In-operation monitoring of the soot load of diesel particulate filters: initial tests. Top Catal. doi: 10.1007/s11244-013-0002-9 Google Scholar
  17. 17.
    Kulkarni VP, Leustek ME, Michels SK, Nair RN, Snopko MA, Knitt AA (2013) Ash detection in diesel particulate filter. U.S. Patent 8,470,070 B2Google Scholar
  18. 18.
    Fremerey P, Reiß S, Geupel A, Fischerauer G, Moos R (2011) Determination of the NOx loading of an automotive lean NOx trap by directly monitoring the electrical properties of the catalyst material itself. Sensors. doi: 10.3390/s110908261 Google Scholar
  19. 19.
    Reiß S, Schönauer D, Hagen G, Fischerauer G, Moos R (2011) Monitoring the ammonia loading of zeolite-based ammonia SCR catalysts by a microwave method. Chem Eng Technol. doi: 10.1002/ceat.201000546 Google Scholar
  20. 20.
    Rauch D, Kubinski D, Simon U, Moos R (2014) Detection of the ammonia loading of a Cu Chabazite SCR catalyst by a radio frequency-based method. Sens Actuators B. doi: 10.1016/j.snb.2014.08.019 Google Scholar
  21. 21.
    Rauch D, Kubinski D, Cavataio G, Upadhyay D (2015) Ammonia loading detection of zeolite SCR catalysts using a radio frequency based method. SAE Int J Engines. doi: 10.4271/2015-01-0986 Google Scholar
  22. 22.
    Dietrich M, Rauch D, Porch A, Moos R (2014) A laboratory test setup for in situ measurements of the dielectric properties of catalyst powder samples under reaction conditions by microwave cavity perturbation: set up and initial tests. Sensors. doi: 10.3390/s140916856 Google Scholar
  23. 23.
    Dietrich M, Rauch D, Simon U, Porch A, Moos R (2015) Ammonia storage studies on H-ZSM-5 zeolites by microwave cavity perturbation: correlation of dielectric properties with ammonia storage. J Sens Sens Syst. doi: 10.5194/jsss-4-263-2015 Google Scholar
  24. 24.
    Sjövall H, Blint RJ, Olsson L (2009) Detailed kinetic modeling of NH3 and H2O adsorption, and NH3 oxidation over Cu-ZSM-5. J Phys Chem C. doi: 10.1021/jp802449s Google Scholar
  25. 25.
    Porch A, Slocombe D, Beutler J, Edwards P, Aldawsari A, Xiao T, Kuznetsov V, Almegren H, Aldrees S, Almaqati N (2012) Microwave treatment in oil refining. Appl Petrochem Res. doi: 10.1007/s13203-012-0016-4 Google Scholar
  26. 26.
    Inoue R, Miwa K, Kitano H, Maeda A, Odate Y, Tanabe E (2004) Highly accurate and real-time determination of resonant characteristics: complex linear regression of the transmission coefficient. IEEE Trans Microw Theory Tech. doi: 10.1109/TMTT.2004.834183 Google Scholar
  27. 27.
    Leong K, Mazierska J (2002) Precise measurements of the Q factor of dielectric resonators in the transmission mode-accounting for noise, crosstalk, delay of uncalibrated lines, coupling loss, and coupling reactance. IEEE Trans Microw Theory Tech. doi: 10.1109/TMTT.2002.802324 Google Scholar
  28. 28.
    Komatsu T, Nunokawa M, Moon IS, Takahara T, Namba S, Yashima T (1994) Kinetic studies of reduction of nitric oxide with ammonia on Cu2+-exchanged zeolites. J Catal. doi: 10.1006/jcat.1994.1229 Google Scholar
  29. 29.
    Rice MJ, Chakraborty AK, Bell AT (1998) A density functional theory study of the interactions of H2O with H-ZSM-5, Cu-ZSM-5, and Co-ZSM-5. J Phys Chem A. doi: 10.1021/jp981108s Google Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • D. Rauch
    • 1
  • M. Dietrich
    • 1
  • T. Simons
    • 2
  • U. Simon
    • 2
  • A. Porch
    • 3
  • R. Moos
    • 1
  1. 1.Department of Functional Materials, Bayreuth Engine Research Center (BERC), Zentrum für Energietechnik (ZET)University of BayreuthBayreuthGermany
  2. 2.Institute of Inorganic Chemistry (IAC)RWTH Aachen UniversityAachenGermany
  3. 3.School of EngineeringCardiff UniversityCardiffWales, UK

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