Ab-Initio calculations of the CO adsorption and dissociation on substitutional Fe-Cu surface alloys relevant to Fischer-Tropsch Synthesis: Bcc-(Cu)Fe(100) and fcc-(Fe)Cu(100)

Elahifard, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1002/sia.5228
  3. Abstract:
  4. Direct CO dissociation is seen the main path of the first step in the Fischer-Tropsch Synthesis (FTS) on the reactive iron surfaces. Cu/Fe alloy film is addressed with various applications over face-centered-cubic (fcc)-Cu and body-centered-cubic (bcc)-Fe in the FTS, i.e. preventing iron carbide formation (through direct CO dissociation) by moderating the surface reactivity and facilitating the reduction of iron surfaces, respectively. In this study by density functional theory, the stable configurations of CO molecule on various Cu/Fe alloys over fcc-Cu(100) and bcc-Fe(100) surfaces with different CO coverage (25% and 50%) have been evaluated. Our results showed that the ensemble effect plays a fundamental role to CO adsorption energy on the surface alloys over bcc-Fe(100); on the other hand, the ligand effect determines the CO stability on the fcc-Cu(100) surface alloys. CO dissociation barrier was also calculated on the surface alloys that showed although the CO dissociation process is thermodynamically possible on the more reactive surface alloys, but according to their high barrier, CO dissociation does not occur directly on these surfaces
  5. Keywords:
  6. CO dissociation ; Ab initio calculations ; Alloy film ; CO dissociations ; Ensemble effect ; Face-centered cubic ; Iron carbide formation ; Ligand effect ; Stable configuration ; Adsorption ; Carbides ; Copper ; Copper alloys ; Density functional theory ; Dissociation ; Fischer-Tropsch synthesis ; Ligands ; Metallic films ; Surface properties ; Iron alloys
  7. Source: Surface and Interface Analysis ; Volume 45, Issue 7 , 2013 , Pages 1081-1087 ; 01422421 (ISSN)
  8. URL: http://onlinelibrary.wiley.com/doi/10.1002/sia.5228/abstract