Computational study of ethanol adsorption and reaction over rutile TiO2 (110) surfaces

Handle URI:
http://hdl.handle.net/10754/597825
Title:
Computational study of ethanol adsorption and reaction over rutile TiO2 (110) surfaces
Authors:
Muir, J. N.; Choi, Y.; Idriss, H.
Abstract:
Studies of the modes of adsorption and the associated changes in electronic structures of renewable organic compounds are needed in order to understand the fundamentals behind surface reactions of catalysts for future energies. Using planewave density functional theory (DFT) calculations, the adsorption of ethanol on perfect and O-defected TiO 2 rutile (110) surfaces was examined. On both surfaces the dissociative adsorption mode on five-fold coordinated Ti cations (Ti 4+ 5c) was found to be more favourable than the molecular adsorption mode. On the stoichiometric surface E ads was found to be equal to 0.85 eV for the ethoxide mode and equal to 0.76 eV for the molecular mode. These energies slightly increased when adsorption occurred on the Ti 4+ 5c closest to the O-defected site. However, both considerably increased when adsorption occurred at the removed bridging surface O; interacting with Ti 3+ cations. In this case the dissociative adsorption becomes strongly favoured (E ads = 1.28 eV for molecular adsorption and 2.27 eV for dissociative adsorption). Geometry and electronic structures of adsorbed ethanol were analysed in detail on the stoichiometric surface. Ethanol does not undergo major changes in its structure upon adsorption with its C-O bond rotating nearly freely on the surface. Bonding to surface Ti atoms is a σ type transfer from the O2p of the ethanol-ethoxide species. Both ethanol and ethoxide present potential hole traps on O lone pairs. Charge density and work function analyses also suggest charge transfer from the adsorbate to the surface, in which the dissociative adsorptions show a larger charge transfer than the molecular adsorption mode. This journal is © 2012 the Owner Societies.
Citation:
Muir JN, Choi Y, Idriss H (2012) Computational study of ethanol adsorption and reaction over rutile TiO2 (110) surfaces. Physical Chemistry Chemical Physics 14: 11910. Available: http://dx.doi.org/10.1039/c2cp40641a.
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Physical Chemistry Chemical Physics
Issue Date:
2012
DOI:
10.1039/c2cp40641a
PubMed ID:
22832869
Type:
Article
ISSN:
1463-9076; 1463-9084
Sponsors:
J.M. thanks Aberdeen Energy future funds for a Ph.D. scholarship. DFT calculations were partially performed at KAUST Supercomputing Laboratory and the National Energy Research Scientific Computing Center (Contract No. DE-AC02-05CH11231). Y.C. thanks Drs. Dodi Heryadi and Jack Deslippe for fruitful discussions of Quantum ESPRESSO.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorMuir, J. N.en
dc.contributor.authorChoi, Y.en
dc.contributor.authorIdriss, H.en
dc.date.accessioned2016-02-25T12:57:21Zen
dc.date.available2016-02-25T12:57:21Zen
dc.date.issued2012en
dc.identifier.citationMuir JN, Choi Y, Idriss H (2012) Computational study of ethanol adsorption and reaction over rutile TiO2 (110) surfaces. Physical Chemistry Chemical Physics 14: 11910. Available: http://dx.doi.org/10.1039/c2cp40641a.en
dc.identifier.issn1463-9076en
dc.identifier.issn1463-9084en
dc.identifier.pmid22832869en
dc.identifier.doi10.1039/c2cp40641aen
dc.identifier.urihttp://hdl.handle.net/10754/597825en
dc.description.abstractStudies of the modes of adsorption and the associated changes in electronic structures of renewable organic compounds are needed in order to understand the fundamentals behind surface reactions of catalysts for future energies. Using planewave density functional theory (DFT) calculations, the adsorption of ethanol on perfect and O-defected TiO 2 rutile (110) surfaces was examined. On both surfaces the dissociative adsorption mode on five-fold coordinated Ti cations (Ti 4+ 5c) was found to be more favourable than the molecular adsorption mode. On the stoichiometric surface E ads was found to be equal to 0.85 eV for the ethoxide mode and equal to 0.76 eV for the molecular mode. These energies slightly increased when adsorption occurred on the Ti 4+ 5c closest to the O-defected site. However, both considerably increased when adsorption occurred at the removed bridging surface O; interacting with Ti 3+ cations. In this case the dissociative adsorption becomes strongly favoured (E ads = 1.28 eV for molecular adsorption and 2.27 eV for dissociative adsorption). Geometry and electronic structures of adsorbed ethanol were analysed in detail on the stoichiometric surface. Ethanol does not undergo major changes in its structure upon adsorption with its C-O bond rotating nearly freely on the surface. Bonding to surface Ti atoms is a σ type transfer from the O2p of the ethanol-ethoxide species. Both ethanol and ethoxide present potential hole traps on O lone pairs. Charge density and work function analyses also suggest charge transfer from the adsorbate to the surface, in which the dissociative adsorptions show a larger charge transfer than the molecular adsorption mode. This journal is © 2012 the Owner Societies.en
dc.description.sponsorshipJ.M. thanks Aberdeen Energy future funds for a Ph.D. scholarship. DFT calculations were partially performed at KAUST Supercomputing Laboratory and the National Energy Research Scientific Computing Center (Contract No. DE-AC02-05CH11231). Y.C. thanks Drs. Dodi Heryadi and Jack Deslippe for fruitful discussions of Quantum ESPRESSO.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.titleComputational study of ethanol adsorption and reaction over rutile TiO2 (110) surfacesen
dc.typeArticleen
dc.identifier.journalPhysical Chemistry Chemical Physicsen
dc.contributor.institutionUniversity of Aberdeen, Aberdeen, United Kingdomen
dc.contributor.institutionSaudi Basic Industries Corporation, Riyadh, Saudi Arabiaen
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