Elucidating the role of extended surface defects at Fe surfaces on CO adsorption and dissociation

Aurab Chakrabarty, El Tayeb Bentria, Salawu Akande Omotayo, Othmane Bouhali, Normand Mousseau, Charlotte S. Becquart, Fadwa El-Mellouhi

Research output: Contribution to journalArticle

Abstract

The adsorption and dissociation of hydrocarbons on metallic surfaces during catalytic reactions in a steam reforming furnace often lead to the carburization of the catalysts and metallic surfaces involved. This process is greatly accelerated by the presence of intrinsic defects like vacancies and grain boundaries and is succeeded by surface to subsurface diffusion of C. We employ both density functional theory and reactive force field molecular dynamics simulations to investigate the effect of surface defects on CO dissociation rate directly related to metal dusting corrosion. We demonstrate that stable surface vacancy clusters with large binding energies accelerate the adsorption of CO molecules by decreasing the corresponding dissociation energies. In addition, we demonstrate that the appearance of multiple GBs at the surface leads to an enhancement of the CO dissociation rate. Furthermore, we demonstrate that the increase in surface roughness by emerging GBs leads to an increase in CO dissociation rate.

Original languageEnglish
Pages (from-to)792-798
Number of pages7
JournalApplied Surface Science
Volume491
DOIs
Publication statusPublished - 15 Oct 2019

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Keywords

  • CO adsorption
  • CO dissociation
  • Grain boundary
  • Iron surface
  • Metal dusting corrosion
  • Reactive force field
  • Surface vacancy clusters

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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