Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface
Abstract
Adsorption and dissociation of hydrocarbons on metallic surfaces represent crucial steps on the path to carburization, eventually leading to dusting corrosion. While adsorption of CO molecules on Fe surface is a barrierless exothermic process, this is not the case for the dissociation of CO into C and O adatoms and the diffusion of C beneath the surface that are found to be associated with large energy barriers. In practice, these barriers can be affected by numerous factors that combine to favour the COFe reaction such as the abundance of CO and other hydrocarbons as well as the presence of structural defects. From a numerical point of view, studying these factors is challenging and a stepbystep approach is necessary to assess, in particular, the influence of the finite box size on the reaction parameters for adsorption and dissociation of CO on metal surfaces. Here, we use density functional theory (DFT) total energy calculations with the climbingimage nudged elastic band method to estimate the adsorption energies and dissociation barriers for different CO coverages with surface supercells of different sizes. We further compute the effect of periodic boundary condition for DFT calculations and find that the contribution from van der Waals interaction inmore »
 Authors:
 Texas A&M University at Qatar, P.O. Box 23874, Doha (Qatar)
 Département de Physique and RQMP, Université de Montréal, Case Postale 6128, Succursale Centreville, Montréal, Québec H3C 3J7 (Canada)
 UMET, UMR CNRS 8207, ENSCL, Université Lille I, 59655 Villeneuve d'Ascq Cédex (France)
 Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825, Doha (Qatar)
 Publication Date:
 OSTI Identifier:
 22597742
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ADSORPTION; BOUNDARY CONDITIONS; CARBON; CARBON MONOXIDE; CARBURIZATION; CORROSION; DEFECTS; DEFORMATION; DENSITY FUNCTIONAL METHOD; DISSOCIATION; ERRORS; HYDROCARBONS; IMAGES; METALS; PERIODICITY; SURFACES; VAN DER WAALS FORCES
Citation Formats
Chakrabarty, Aurab, Email: aurab.chakrabarty@qatar.tamu.edu, Bouhali, Othmane, Mousseau, Normand, Becquart, Charlotte S., and ElMellouhi, Fedwa. Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface. United States: N. p., 2016.
Web. doi:10.1063/1.4959990.
Chakrabarty, Aurab, Email: aurab.chakrabarty@qatar.tamu.edu, Bouhali, Othmane, Mousseau, Normand, Becquart, Charlotte S., & ElMellouhi, Fedwa. Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface. United States. doi:10.1063/1.4959990.
Chakrabarty, Aurab, Email: aurab.chakrabarty@qatar.tamu.edu, Bouhali, Othmane, Mousseau, Normand, Becquart, Charlotte S., and ElMellouhi, Fedwa. 2016.
"Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface". United States.
doi:10.1063/1.4959990.
@article{osti_22597742,
title = {Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface},
author = {Chakrabarty, Aurab, Email: aurab.chakrabarty@qatar.tamu.edu and Bouhali, Othmane and Mousseau, Normand and Becquart, Charlotte S. and ElMellouhi, Fedwa},
abstractNote = {Adsorption and dissociation of hydrocarbons on metallic surfaces represent crucial steps on the path to carburization, eventually leading to dusting corrosion. While adsorption of CO molecules on Fe surface is a barrierless exothermic process, this is not the case for the dissociation of CO into C and O adatoms and the diffusion of C beneath the surface that are found to be associated with large energy barriers. In practice, these barriers can be affected by numerous factors that combine to favour the COFe reaction such as the abundance of CO and other hydrocarbons as well as the presence of structural defects. From a numerical point of view, studying these factors is challenging and a stepbystep approach is necessary to assess, in particular, the influence of the finite box size on the reaction parameters for adsorption and dissociation of CO on metal surfaces. Here, we use density functional theory (DFT) total energy calculations with the climbingimage nudged elastic band method to estimate the adsorption energies and dissociation barriers for different CO coverages with surface supercells of different sizes. We further compute the effect of periodic boundary condition for DFT calculations and find that the contribution from van der Waals interaction in the computation of adsorption parameters is important as they contribute to correcting the finitesize error in small systems. The dissociation process involves carbon insertion into the Fe surface causing a lattice deformation that requires a larger surface system for unrestricted relaxation. We show that, in the larger surface systems associated with dilute COcoverages, Cinsertion is energetically more favourable, leading to a significant decrease in the dissociation barrier. This observation suggests that a large surface system with dilute coverage is necessary for all similar metalhydrocarbon reactions in order to study their fundamental electronic mechanisms, as an isolated phenomenon, free from finitesize effects.},
doi = {10.1063/1.4959990},
journal = {Journal of Applied Physics},
number = 5,
volume = 120,
place = {United States},
year = 2016,
month = 8
}

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