Topics in Catalysis

, 52:1734 | Cite as

Study of Ammonia Formation During the Purge of a Lean NO x Trap

  • A. KouakouEmail author
  • F. Dhainaut
  • P. Granger
  • F. Fresnet
  • I. Louis-Rose
Original Paper


The aim of this work was to study the formation of ammonia during the regeneration step of a commercial lean NO x Trap catalyst in real conditions. Experiments were carried out on an engine test bench equipped with 2.2 L common rail diesel engine. The after-treatment system was composed of a commercial NSR monolith catalyst with a volume of 2.2 L. This material was composed of platinum, palladium and rhodium, as active components, with barium oxide and alumina as storage component and support, respectively. Catalytic measurements were carried out at 280 °C. Particular attention has been paid to formation of ammonia during the purge using hydrogen and CO as reducing agents. The time dependency of the extent of ammonia formation and the influence of hydrogen concentration were carefully examined. It was observed that the temperature rose in the first step of the regeneration process, after the switch in rich conditions, due to the occurrence of exothermic oxidation (H2/O2, CO/O2) accompanied with the releasing of available vacant noble metal sites which may provide a route for H2 and NO dissociation and/or subsequent surface reactions leading to the ultimate formation of ammonia. It was found that ammonia formation strongly depends on the purge duration and on the concentration of the reducing agent available during the purge.


NOx-trap reduction catalyst Noble metal Ammonia 


  1. 1.
    Lietti L, Nova I, Forzatti P (2008) J Catal 257:270CrossRefGoogle Scholar
  2. 2.
    Szailer T, Kwak JH, Kim DH, Hanson JC, Peden CHF, Szanyi JJ (2006) J Catal 239:51CrossRefGoogle Scholar
  3. 3.
    Takahashi N, Shinjoh H, Iijima T, Suzuki T, Yamazaki K, Yokota K, Suzuki H, Miyoshi N, Matsumoto S, Tanizawa T (1996) Catal Today 27:63CrossRefGoogle Scholar
  4. 4.
    Breen JP, Rioche C, Burch R, Hardacre C, Meunier FC (2007) Appl Catal B 72:178CrossRefGoogle Scholar
  5. 5.
    Clayton RD, Harold MP, Balakotaiah V (2008) Appl Catal B 84:616CrossRefGoogle Scholar
  6. 6.
    Koci P, Plat F, Stepanek J, Marek M (2008) Catal Today 137:253CrossRefGoogle Scholar
  7. 7.
    Breen JP, Burch R, Fontaine-Gautrelet C, Hardacre C, Rioche C (2008) Appl Catal B 81:150CrossRefGoogle Scholar
  8. 8.
    Konrad B, Krutzsch B (2001) US patent 617607079B1Google Scholar
  9. 9.
    Weibel M, Waldlüβer N, Wunsh R, Chatterjee D, Bandl-Konrad B, Krutzch B (2008) Proceedings of the international congress on catalysis and automotive pollution control (Capoc 8) 1:1Google Scholar
  10. 10.
    Lui Z, Anderson JA (2004) J Catal 224:18CrossRefGoogle Scholar
  11. 11.
    Epling WS, Campbell LE, Yezerets A, Currier NW, Parks JE (2004) Catal Rev 46:163CrossRefGoogle Scholar
  12. 12.
    Pihl JA, Parks II JE, Daw CS, Root TW (2006) SAE Tech. Paper 2006-01-3441Google Scholar
  13. 13.
    Cumaranatunge L, Mulla SS, Yezerets A, Currier NW, Delgass WN, Ribeiro FH (2007) J Catal 246:29CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • A. Kouakou
    • 1
    • 2
    Email author
  • F. Dhainaut
    • 2
  • P. Granger
    • 2
  • F. Fresnet
    • 1
  • I. Louis-Rose
    • 3
  1. 1.Renault, TechnocentreGuyancourtFrance
  2. 2.UCCSVilleneuve d’AscqFrance
  3. 3.RenaultCT LardyFrance

Personalised recommendations