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In situ determination of the nanostructure effects on the activity, stability and selectivity of Pt-Sn ethanol oxidation catalysts

In situ determination of the nanostructure effects on the activity, stability and selectivity of Pt-Sn ethanol oxidation catalysts
In situ determination of the nanostructure effects on the activity, stability and selectivity of Pt-Sn ethanol oxidation catalysts
Nanoparticle catalysts comprising two PtSn alloys with different Pt:Sn atomic ratios and a Sn modified Pt catalyst were prepared in order to study the effect of the particle nanostructures on the activity towards the ethanol electrooxidation and the selectivity to CO2. An accurate model of the electronic and structural properties, obtained by ex situ analysis, was established. Alloying of Sn with Pt causes the expansion of the lattice parameter of Pt and modifies its electronic structure. In contrast, the deposition of Sn on the Pt surface has neither effect. The activity of the catalysts towards ethanol oxidation was established voltammetrically and the CO2 selectivity via in situ Fourier transform infrared spectroscopy (FTIRS). Results indicated that the modification of the electronic environment of Pt in Pt-Sn alloys results in a weaker adsorption of the intermediates (acetaldehyde and acetic acid), which desorb easily from the surface of the catalyst resulting in incomplete oxidation to CO2. In contrast,
when the electronic structure is not perturbed (Sn modified Pt sample), the amount of CO2 produced increases. The stability of the different nanostructures under working conditions was investigated by in situ X-ray absorption spectroscopy (XAS) measurements, which show that initially both the Sn modified Pt and Pt-Sn alloy nanostructures are stable under applied potential in the potential window studied and in presence of ethanol. Accelerated aging studies showed that the Sn modified Pt nanostructure remained stable, whereas a significant structural change was observed for the Pt-Sn alloys.
Pt-Sn nanostructures, Ethanol electrooxidation, In situ FTIRS; , In situ XAFS, structural stability
1572-6657
136-144
Calvillo, Laura
05ff21ed-97ce-4ea4-9b73-f4c181be59b0
Mendez De Leo, Lucila
bb67f217-ade1-42b2-b4e8-68bb68fb118c
Thompson, Stephen J.
46677911-01d9-478e-ad98-87ac37cd56a6
Price, Stephen W.T.
42cf4966-68f0-443a-a933-d198f3dc60c2
Calvo, Ernesto J.
1e3276b3-088d-4061-a2b7-6ab073c714d8
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Calvillo, Laura
05ff21ed-97ce-4ea4-9b73-f4c181be59b0
Mendez De Leo, Lucila
bb67f217-ade1-42b2-b4e8-68bb68fb118c
Thompson, Stephen J.
46677911-01d9-478e-ad98-87ac37cd56a6
Price, Stephen W.T.
42cf4966-68f0-443a-a933-d198f3dc60c2
Calvo, Ernesto J.
1e3276b3-088d-4061-a2b7-6ab073c714d8
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169

Calvillo, Laura, Mendez De Leo, Lucila, Thompson, Stephen J., Price, Stephen W.T., Calvo, Ernesto J. and Russell, Andrea E. (2018) In situ determination of the nanostructure effects on the activity, stability and selectivity of Pt-Sn ethanol oxidation catalysts. Journal of Electroanalytical Chemistry, 819, 136-144. (doi:10.1016/j.jelechem.2017.09.060).

Record type: Article

Abstract

Nanoparticle catalysts comprising two PtSn alloys with different Pt:Sn atomic ratios and a Sn modified Pt catalyst were prepared in order to study the effect of the particle nanostructures on the activity towards the ethanol electrooxidation and the selectivity to CO2. An accurate model of the electronic and structural properties, obtained by ex situ analysis, was established. Alloying of Sn with Pt causes the expansion of the lattice parameter of Pt and modifies its electronic structure. In contrast, the deposition of Sn on the Pt surface has neither effect. The activity of the catalysts towards ethanol oxidation was established voltammetrically and the CO2 selectivity via in situ Fourier transform infrared spectroscopy (FTIRS). Results indicated that the modification of the electronic environment of Pt in Pt-Sn alloys results in a weaker adsorption of the intermediates (acetaldehyde and acetic acid), which desorb easily from the surface of the catalyst resulting in incomplete oxidation to CO2. In contrast,
when the electronic structure is not perturbed (Sn modified Pt sample), the amount of CO2 produced increases. The stability of the different nanostructures under working conditions was investigated by in situ X-ray absorption spectroscopy (XAS) measurements, which show that initially both the Sn modified Pt and Pt-Sn alloy nanostructures are stable under applied potential in the potential window studied and in presence of ethanol. Accelerated aging studies showed that the Sn modified Pt nanostructure remained stable, whereas a significant structural change was observed for the Pt-Sn alloys.

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Submitted date: 29 June 2017
Accepted/In Press date: 27 September 2017
e-pub ahead of print date: 28 September 2017
Published date: 15 June 2018
Keywords: Pt-Sn nanostructures, Ethanol electrooxidation, In situ FTIRS; , In situ XAFS, structural stability

Identifiers

Local EPrints ID: 415313
URI: https://eprints.soton.ac.uk/id/eprint/415313
ISSN: 1572-6657
PURE UUID: 319e2405-8079-4883-8eab-7af247dfa651
ORCID for Andrea E. Russell: ORCID iD orcid.org/0000-0002-8382-6443

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Date deposited: 07 Nov 2017 17:30
Last modified: 14 Mar 2019 05:28

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Contributors

Author: Laura Calvillo
Author: Lucila Mendez De Leo
Author: Stephen J. Thompson
Author: Stephen W.T. Price
Author: Ernesto J. Calvo

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