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Potential dependence of segregation and surface alloy formation of a Ru modified carbon supported Pt catalyst

Rose, A.; Crabb, E.M.; Qian, Y.; Ravikumar, M.K.; Wells, P.; Wiltshire, R.J.K.; Yao, J.; Bilsborrow, R.; Mosselmans, F. and Russell, A.E. (2007). Potential dependence of segregation and surface alloy formation of a Ru modified carbon supported Pt catalyst. Electrochimica Acta, 52(18) pp. 5556–5564.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1016/j.electacta.2007.02.023
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Abstract

Ruthenium modified carbon supported platinum catalysts have been shown to have a similar activity towards carbon monoxide oxidation as conventionally prepared bimetallic PtRu alloy catalysts. In this study the effect of the applied electrode potential and potential cycles on the location and oxidation state of the Ru species in such Ru modified Pt/C catalysts was investigated using in situ EXAFS collected at both the Ru K and Pt L3 absorption edges. The as prepared catalyst was found to consist of a Pt core with a Ru oxy/hydroxide shell. The potential dependent data indicated alloying to form a PtRu phase at 0.05 V versus RHE and subsequent dealloying to return to the Ru oxy/hydroxide decorated Pt surface at potentials greater than 0.7 V. The Ru–O distances obtained indicate that both Ru3+ and Ru4+ species are present on the surface of the Pt particles at oxidising potentials; the former is characteristic of the as prepared Ru modified Pt/C catalyst and following extensive periods at potentials above 0.7 V and the latter of the Ru oxide species on the PtRu alloy.

Item Type: Journal Article
ISSN: 0013-4686
Keywords: Ruthenium; Platinum; Fuel cell catalysts; EXAFS; CO oxidation
Academic Unit/Department: Science > Life, Health and Chemical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
eSTEeM
Biomedical Research Network (BRN)
Item ID: 8841
Depositing User: Eleanor Crabb
Date Deposited: 02 Aug 2007
Last Modified: 07 Mar 2014 13:42
URI: http://oro.open.ac.uk/id/eprint/8841
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