Competing ternary surface reaction CO + O2 +H2 on Ir(111)

Kevin Rohe, Jaime Cisternas, Stefan Wehner

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


All rights reserved. The CO oxidation on platinum-group metals under ultra-high-vacuum conditions is one of the most studied surface reactions. However, the presence of disturbing species and competing reactions are often neglected.One of the most interesting additional gases to be treated is hydrogen, due to its importance in technical applications and its inevitability under vacuum conditions. Adding hydrogen to the reaction of CO and O2 leads to more adsorbed species and competing reaction steps towards water formation. In this study, a model for approaching the competing surface reactions CO + O2 + H2 is presented and discussed. Using the framework of bifurcation theory, we show how the steady states of the extended system correspond to a swallowtail catastrophe set with a tristable regime within the swallowtail. We explore numerically the possibility of reaching all stable states and illustrate the experimental challenges such a system could pose. Lastly, an approximative firstprinciple approach to diffusion illustrates how up to three stable states balance each other while forming heterogeneous patterns.
Original languageAmerican English
JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Issue number2236
StatePublished - 1 Apr 2020


  • Competitive surface reaction
  • Ir(111)
  • Langmuir-Hinshelwood mechanism
  • Reaction-diffusion system
  • Swallowtail catastrophe
  • Tristability

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