The modification of platinum single crystals for fuel cell electrocatalysis
The modification of platinum single crystals for fuel cell electrocatalysis
Ruthenium has been vapour deposited on a Pt(l 11) single crystal surface in UHV and characterised by LEISS, XPS and LEED. These characterised surfaces have then been cleanly transferred to an electrochemical environment where their activity towards CO electro-oxidation was investigated using cyclic voltammetry. The modiGcation of Pt(l 11) by ruthenium gives rise to two distinct and separate CO adsorption regions. This is ascribed to the oxidation of CO which is adsorbed directly adjacent to the edges of the clusters of ruthenium, and to CO which is adsorbed a few atoms away from the ruthenium islands. The promotion of the electrooxidation of CO has been assigned to the activation of water adsorption on the ruthenium islands and the subsequent spill-over of the adsorbed water species. Two ordered surface alloys of tin, Pt(lll)/Sn(2x2) and Pt(lll)/Sn(V3xV3)R30° have been prepared and characterised by the above UHV spectroscopic techniques. Cyclic voltammetiy has been performed on these surface alloys, and a sharp redox feature associated with the hydroxide adsorption / desorption is observed at 0 . 2 8 Va & 0 . 1 6 Vc vs. RHE. The onset of CO oxidation on these surfaces is concomitant with the surface oxidation peak, and the peak maximum for CO oxidation occurs at ca. 0.40V lower than on bare platinum. The coincident onset of the CO electro-oxidation with the Sn oxidation on the alloy surface is the first time the operation of bi-functional mechanism has been observed unambiguously.
University of Southampton
Rendall, Michael Edward
51d0430a-76c2-4f09-9912-0ebe74f603af
2003
Rendall, Michael Edward
51d0430a-76c2-4f09-9912-0ebe74f603af
Rendall, Michael Edward
(2003)
The modification of platinum single crystals for fuel cell electrocatalysis.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Ruthenium has been vapour deposited on a Pt(l 11) single crystal surface in UHV and characterised by LEISS, XPS and LEED. These characterised surfaces have then been cleanly transferred to an electrochemical environment where their activity towards CO electro-oxidation was investigated using cyclic voltammetry. The modiGcation of Pt(l 11) by ruthenium gives rise to two distinct and separate CO adsorption regions. This is ascribed to the oxidation of CO which is adsorbed directly adjacent to the edges of the clusters of ruthenium, and to CO which is adsorbed a few atoms away from the ruthenium islands. The promotion of the electrooxidation of CO has been assigned to the activation of water adsorption on the ruthenium islands and the subsequent spill-over of the adsorbed water species. Two ordered surface alloys of tin, Pt(lll)/Sn(2x2) and Pt(lll)/Sn(V3xV3)R30° have been prepared and characterised by the above UHV spectroscopic techniques. Cyclic voltammetiy has been performed on these surface alloys, and a sharp redox feature associated with the hydroxide adsorption / desorption is observed at 0 . 2 8 Va & 0 . 1 6 Vc vs. RHE. The onset of CO oxidation on these surfaces is concomitant with the surface oxidation peak, and the peak maximum for CO oxidation occurs at ca. 0.40V lower than on bare platinum. The coincident onset of the CO electro-oxidation with the Sn oxidation on the alloy surface is the first time the operation of bi-functional mechanism has been observed unambiguously.
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Published date: 2003
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Local EPrints ID: 465104
URI: http://eprints.soton.ac.uk/id/eprint/465104
PURE UUID: 0d789e8a-d634-4319-96ba-c89c4c87a675
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Date deposited: 05 Jul 2022 00:23
Last modified: 16 Mar 2024 19:57
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Author:
Michael Edward Rendall
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