Catalysis Letters

, Volume 8, Issue 5–6, pp 359–366 | Cite as

Potassium promotion of the ammonia synthesis reaction: A combined UHV-high pressure investigation

  • Eric Törnqvist
  • Andrew A. Chen


The ammonia synthesis rate has been measured as a function of the potassium coverage of a polycrystalline iron foil. The results clearly demonstrate a promoting effect of the potassium in agreement with the work of Ertl et al. on the dissociative dinitrogen adsorption at iron single crystal surfaces. However, the results also imply a marked difference between the state of the surface under ammonia synthesis conditions and during the dinitrogen adsorption experiments in ultra-high vacuum. It is suggested that in the former case the potassium atoms are surrounded by several strongly adsorbed atoms effectively blocking the corresponding sites for dinitrogen dissociation.


Potassium promotion iron based catalysts ammonia synthesis high pressure — ultra high vacuum (UHV) investigation 


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Copyright information

© J.C. Baltzer A.G. Scientific Publishing Company 1991

Authors and Affiliations

  • Eric Törnqvist
    • 1
  • Andrew A. Chen
    • 1
  1. 1.Holder Topsøe Research LaboratoriesLyngbyDenmark

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