The Influence of Water and Hydroxyl on a Bimetallic (√3 x √3)R30° Sn/Pt Surface Alloy

McBride, F ORCID: 0000-0003-2985-3173, Darling, GR ORCID: 0000-0001-9329-9993, Pussi, K, Lucas, CA ORCID: 0000-0001-5743-3868, Gruender, Y ORCID: 0000-0002-5295-0927, Darlington, M, Brownrigg, A and Hodgson, A ORCID: 0000-0001-8677-7467 (2013) The Influence of Water and Hydroxyl on a Bimetallic (√3 x √3)R30° Sn/Pt Surface Alloy. JOURNAL OF PHYSICAL CHEMISTRY C, 117 (8). pp. 4032-4039.

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Official URL: http://dx.doi.org/10.1021/jp3112342

Abstract

Tin-platinum alloy surfaces show a remarkable activity in the fuel cell reaction, oxidizing and removing CO that would otherwise block reaction on pure Pt. This so-called "bifunctional" mechanism has been attributed to OH adsorption on Sn and CO adsorption on Pt, reducing site competition, and poisoning by CO. In this study, we examine the effect of water adsorption on the structure of the ordered Sn/Pt(111) (√3 × √3)R30° surface alloy in order to relate the existing structural data on the behavior of Sn/Pt surfaces to the nature of the adsorbate. The Sn/Pt surface structure was investigated by surface X-ray diffraction (SXRD) and low-energy electron diffraction, and compared to theoretical models obtained from density functional theory and with structural determinations from previous in situ electrochemical experiments. We find that adsorbed water induces a 0.16 Å outward relaxation in the Sn position, similar to that previously ascribed to OH adsorption in electrochemical SXRD measurements. We review the evidence for specific OH adsorption on Sn and suggest that the simple site-based explanation for the activity of this surface to CO is inconsistent with the observed expansion. © 2013 American Chemical Society.

Item Type:	Article
Additional Information:	Export Date: 17 February 2014Source: Scopus## TULIP Type: Articles/Papers (Journal) ##
Depositing User:	Symplectic Admin
Date Deposited:	20 Jul 2015 10:31
Last Modified:	05 Oct 2023 11:37
DOI:	10.1021/jp3112342
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/2004100