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The influence of Pt particle size on the surface oxidation of titania supported platinum

The influence of Pt particle size on the surface oxidation of titania supported platinum
The influence of Pt particle size on the surface oxidation of titania supported platinum
A range of reduced titania (TiOx) supported platinum electrocatalysts have been synthesised using physical vapour deposition on arrays of electrodes. Surfaces with equivalent thicknesses of platinum in the range 0.2–2.5 nm on a uniform layer of TiOx have been synthesised on 10 × 10 arrays. The arrays have been used to study the surface redox chemistry of the supported platinum as well as the oxidation of a monolayer of carbon monoxide on the platinum.

It is shown that below an equivalent thickness of 0.8 nm, there is a positive shift in the potential for the oxidation of the platinum surface and a negative shift for the reduction of the oxide with decrease in the platinum loading. These shifts show that it is the kinetics of the platinum/platinum oxide couple that change with platinum loading; the couple becomes increasingly irreversible with decreasing loading. The peak potential for the oxidation of the monolayer of carbon monoxide also shifts positive and broadens with decreasing platinum loading; these trends are again particularly marked below an equivalent thickness of 0.8 nm while below 0.4 nm no CO oxidation peak is observed although it could be confirmed that CO is adsorbed on such surfaces. Again, these changes with platinum loading are associated with the irreversibility of the platinum/platinum oxide couple.
At low equivalent thicknesses, it is impossible to form the oxidised platinum species within the carbon monoxide monolayer essential to the commencement of oxidation of the CO monolayer.
1463-9076
1564-1570
Hayden, Brian E.
aea74f68-2264-4487-9d84-5b12ddbbb331
Pletcher, Derek
f22ebe69-b859-4a89-80b0-9e190e6f8f30
Suchsland, Jens-Peter
3251dda4-1257-44af-b894-846ef5298133
Williams, Laura J.
98101e5d-f6cb-451c-81ae-06b1086e752e
Hayden, Brian E.
aea74f68-2264-4487-9d84-5b12ddbbb331
Pletcher, Derek
f22ebe69-b859-4a89-80b0-9e190e6f8f30
Suchsland, Jens-Peter
3251dda4-1257-44af-b894-846ef5298133
Williams, Laura J.
98101e5d-f6cb-451c-81ae-06b1086e752e

Hayden, Brian E., Pletcher, Derek, Suchsland, Jens-Peter and Williams, Laura J. (2009) The influence of Pt particle size on the surface oxidation of titania supported platinum. Physical Chemistry Chemical Physics, 11 (10), 1564-1570. (doi:10.1039/b817553e).

Record type: Article

Abstract

A range of reduced titania (TiOx) supported platinum electrocatalysts have been synthesised using physical vapour deposition on arrays of electrodes. Surfaces with equivalent thicknesses of platinum in the range 0.2–2.5 nm on a uniform layer of TiOx have been synthesised on 10 × 10 arrays. The arrays have been used to study the surface redox chemistry of the supported platinum as well as the oxidation of a monolayer of carbon monoxide on the platinum.

It is shown that below an equivalent thickness of 0.8 nm, there is a positive shift in the potential for the oxidation of the platinum surface and a negative shift for the reduction of the oxide with decrease in the platinum loading. These shifts show that it is the kinetics of the platinum/platinum oxide couple that change with platinum loading; the couple becomes increasingly irreversible with decreasing loading. The peak potential for the oxidation of the monolayer of carbon monoxide also shifts positive and broadens with decreasing platinum loading; these trends are again particularly marked below an equivalent thickness of 0.8 nm while below 0.4 nm no CO oxidation peak is observed although it could be confirmed that CO is adsorbed on such surfaces. Again, these changes with platinum loading are associated with the irreversibility of the platinum/platinum oxide couple.
At low equivalent thicknesses, it is impossible to form the oxidised platinum species within the carbon monoxide monolayer essential to the commencement of oxidation of the CO monolayer.

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Published date: 20 January 2009

Identifiers

Local EPrints ID: 159679
URI: http://eprints.soton.ac.uk/id/eprint/159679
ISSN: 1463-9076
PURE UUID: d6514342-c22f-473a-96ff-7c864aa6e090
ORCID for Brian E. Hayden: ORCID iD orcid.org/0000-0002-7762-1812

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Date deposited: 05 Jul 2010 15:09
Last modified: 26 Nov 2019 02:07

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