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

Kevin Rohe, Jaime Cisternas, Stefan Wehner

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1 Scopus citations

Abstract

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 languageEnglish
Article number20190712
JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume476
Issue number2236
DOIs
StatePublished - 1 Apr 2020

Bibliographical note

Funding Information:
Data accessibility. Python codes for numerical simulations can be accessed in the electronic supplementary material. Authors’ contributions. K.R. worked on the model, the numerical simulation of the experiment and drafted §§2 and 4. J.C. worked on the bifurcation analysis, diffusion and drafted §§3 and 5. S.W. worked on the model, gave important information about the experiment and drafted §1. All authors contributed to the interpretation of the results and the revision of the article. All authors gave their final approval of the manuscript. Competing interests. We declare we have no competing interests. Funding. J.C. acknowledges the financial support of FONDECYT Project 1170460. K.R., J.C. and S.W. are grateful for the financial support of the Erasmus+ mobility programme of the European Union.

Funding Information:
J.C. acknowledges the financial support of FONDECYT Project 1170460. K.R., J.C. and S.W. are grateful for the financial support of the Erasmus+ mobility programme of the European Union.

Publisher Copyright:
© 2020 The Author(s) Published by the Royal Society. All rights reserved.

Keywords

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

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