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Computational investigation of CO adsorbed on Aux, Agx and (AuAg)x nanoclusters (x = 1-5, 147) and monometallic Au and Ag low-energy surfaces

Catlow, Charles Richard A. and Logsdail, Andrew 2018. Computational investigation of CO adsorbed on Aux, Agx and (AuAg)x nanoclusters (x = 1-5, 147) and monometallic Au and Ag low-energy surfaces. European Physical Journal B 91 , 32. 10.1140/epjb/e2017-80280-7

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Abstract

Density functional theory calculations have been performed investigating the use of CO as a probe molecule for determining the structure and composition of Au, Ag AuAg nanoparticles. For very small nanoclusters (x = 1-5), vibrational frequencies can be directly correlated to CO adsorption strength, whereas larger 147-atom nanoparticles showed a strong energetic preference for CO adsorption at a vertex position but the highest wavenumbers are calculated for the bridge positions. We also studied CO adsorption on Au and Ag (100) and (111) surfaces, for a 1 monolayer coverage, and this proves to be energetically favourable only on atop and bridge positions for Au (100) and atop for Ag (100); vibrational frequencies for the CO molecule red-shift to lower wavenumbers as a result of increased metal coordination. We conclude that vibrational frequencies cannot be relied upon solely in order to obtain accurate compositional analysis, but we do believe that elemental rearrangement in the nanocluster from Ag@Au (or Au@Ag) to an alloy would result in a shift in the vibrational frequencies that indicate the change in the surface composition.

Item Type: Article
Date Type: Published Online
Status: Published
Schools: Advanced Research Computing @ Cardiff (ARCCA)
Chemistry
Publisher: Springer Verlag
ISSN: 1434-6028
Date of First Compliant Deposit: 28 November 2017
Date of Acceptance: 11 July 2017
Last Modified: 29 Dec 2018 21:47
URI: http://orca-mwe.cf.ac.uk/id/eprint/107112

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