Formamide adsorption over the TiO2 (110) surface: a theoretical study

P. R. McGill; J. M. R. Muir; H. Idriss; T. Söhnel

doi:10.1039/C3RA41286E

Formamideadsorption over the TiO₂ (110) surface: a theoretical study

P. R. McGill,^a J. M. R. Muir,^bc H. Idriss^bd and T. Söhnel*^ae

* Corresponding authors

^a School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
E-mail: t.soehnel@auckland.ac.nz
Tel: 0064 9 373 7599 ext 89722

^b Department of Chemistry, The University of Aberdeen, Aberdeen AB24 3UE, UK

^c Department of Earth Sciences, University College London, London WC1E 6BT, UK

^d Chemical Catalysis, SABIC T&I (Riyadh) and CRI (KAUST), Saudi Arabia

^e Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, New Zealand

Abstract

The adsorption of monomeric formamide over the rutile TiO₂ (110) surface has been studied by way of density functional theory. At a coverage of one formamide per two surface repeat units, there is very little difference in stability between molecular and dissociative adsorption configurations. At larger coverages, however, dissociative adsorption in a manner analogous to that observed for carboxylic acid becomes favoured. Stable adsorption modes for the initial steps of a formic acid-like decomposition route are also studied. In the presence of an oxygen vacancy, dissociatively adsorbed formamide bonds with either its N (or O) atom above the oxygen vacancy while the other atom (N or O) coordinates to a five-fold coordinated surface titanium atom. Both modes of adsorption are however found to be isoenergetic. Results provide a possible explanation for the experimentally observed nitriding of the TiO₂ surface post adsorption. Density of States analyses indicated that the nature of interaction is mainly covalent with large degree of hybridisation between the formamide orbitals and surface states.

Article information

https://doi.org/10.1039/C3RA41286E

Article type

Paper

Submitted

18 Mar 2013

Accepted

03 Jul 2013

First published

08 Jul 2013

Download Citation

RSC Adv., 2013,3, 16829-16839

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Formamide adsorption over the TiO₂ (110) surface: a theoretical study

P. R. McGill, J. M. R. Muir, H. Idriss and T. Söhnel, RSC Adv., 2013, 3, 16829 DOI: 10.1039/C3RA41286E

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