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The role of the three-phase boundary of the platinum-support interface in catalysis: A model catalyst kinetic study

Lookup NU author(s): Dr Evangelos PapaioannouORCiD, Christoph Bachmann, Dr Daniel Frankel, Professor Ian MetcalfeORCiD

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Abstract

A series of microstructured, supported platinum (Pt) catalyst films (supported on single crystal yttria-stabilized zirconia) and an appropriate Pt catalyst reference system (supported on single crystal alumina) were fabricated using pulsed laser deposition and argon etching. The thin films exhibit area-specific lengths of three-phase boundary (length of three-phase boundary between the Pt, support and fluid phase divided by the superficial area of the sample) that vary over four orders of magnitude from 4.5 × 10² m m^-2 to 4.9 × 10⁶ m m^-2 equivalent to structural lengthscales of 0.2 µm to approximately 9000 µm. The catalyst films are characterised using X-ray diffraction, atomic force microscopy, high-resolution scanning electron microscopy, and catalytic activity tests employing the carbon monoxide oxidation reaction. When Pt is supported on yttria-stabilized zirconia, the reaction rate clearly depends upon the area-specific length of the three-phase boundary, l(tpb). A similar relationship is not observed when Pt is supported on alumina. We tentatively suggest that the presence of the three-phase boundary provides an extra channel of oxygen supply to the Pt through diffusion in or on the yttria-stabilized zirconia support coupled with surface diffusion across the Pt.

Publication metadata

Author(s): Papaioannou EI, Bachmann C, Neumeier JJ, Frankel D, Over H, Janek J, Metcalfe IS

Publication type: Article

Publication status: Published

Journal: ACS Catalysis

Year: 2016

Volume: 6

Pages: 5865-5872

Online publication date: 22/07/2016

Acceptance date: 11/07/2016

Date deposited: 22/07/2016

ISSN (electronic): 2155-5435

Publisher: American Chemical Society

URL: http://dx.doi.org/10.1021/acscatal.6b00829

DOI: 10.1021/acscatal.6b00829

Data Access Statement: http://dx.doi.org/10.17634/081371-1

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