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Ideal vs real: simulated annealing of experimentally derived and geometric platinum nanoparticles

Ideal vs real: simulated annealing of experimentally derived and geometric platinum nanoparticles
Ideal vs real: simulated annealing of experimentally derived and geometric platinum nanoparticles
Platinum nanoparticles find significant use as catalysts in industrial applications such as fuel cells. Research into their design has focussed heavily on nanoparticle size and shape as they greatly influence activity. Using high throughput, high precision electron microscopy, the structures of commercially available Pt catalysts have been determined, and we have used classical and quantum atomistic simulations to examine and compare them with geometric cuboctahedral and truncated octahedral structures. A simulated annealing procedure was used both to explore the potential energy surface at different temperatures, and also to assess the effect on catalytic activity that annealing would have on nanoparticles with different geometries and sizes. The differences in response to annealing between the real and geometric nanoparticles are discussed in terms of thermal stability, coordination number and the proportion of optimal binding sites on the surface of the nanoparticles. We find that annealing both experimental and geometric nanoparticles results in structures that appear similar in shape and predicted activity, using oxygen adsorption as a measure. Annealing is predicted to increase the catalytic activity in all cases except the truncated octahedra, where it has the opposite effect. As our simulations have been performed with a classical force field, we also assess its suitability to describe the potential energy of such nanoparticles by comparing with large scale density functional theory calculations.
0953-8984
Ellaby, Tom
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Aarons, Jolyon
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Varambhia, Aakash
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Jones, Lewys
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Nellist, Peter D.
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Ozkaya, Dogan
d6b30e54-3986-41af-a129-d20c42ff94d7
Sarwar, Misbah
ae93ef8f-8a84-4a46-95ac-cd9352c44e56
Thompsett, David
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Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61
Ellaby, Tom
7f85bf66-4204-49b1-a388-aff6cea19077
Aarons, Jolyon
93e68133-73b0-43e0-8c91-464920f4a503
Varambhia, Aakash
78a03233-af29-4426-a25e-188e51099fe9
Jones, Lewys
9befb123-3e38-4c64-a92b-adc935b50737
Nellist, Peter D.
f237015c-a26a-473c-960e-de99f2ef5a2d
Ozkaya, Dogan
d6b30e54-3986-41af-a129-d20c42ff94d7
Sarwar, Misbah
ae93ef8f-8a84-4a46-95ac-cd9352c44e56
Thompsett, David
2fba717f-67ed-4999-b400-3c3a0681778f
Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61

Ellaby, Tom, Aarons, Jolyon, Varambhia, Aakash, Jones, Lewys, Nellist, Peter D., Ozkaya, Dogan, Sarwar, Misbah, Thompsett, David and Skylaris, Chris-Kriton (2018) Ideal vs real: simulated annealing of experimentally derived and geometric platinum nanoparticles. Journal of Physics: Condensed Matter, 30 (15). (doi:10.1088/1361-648X/aab251).

Record type: Article

Abstract

Platinum nanoparticles find significant use as catalysts in industrial applications such as fuel cells. Research into their design has focussed heavily on nanoparticle size and shape as they greatly influence activity. Using high throughput, high precision electron microscopy, the structures of commercially available Pt catalysts have been determined, and we have used classical and quantum atomistic simulations to examine and compare them with geometric cuboctahedral and truncated octahedral structures. A simulated annealing procedure was used both to explore the potential energy surface at different temperatures, and also to assess the effect on catalytic activity that annealing would have on nanoparticles with different geometries and sizes. The differences in response to annealing between the real and geometric nanoparticles are discussed in terms of thermal stability, coordination number and the proportion of optimal binding sites on the surface of the nanoparticles. We find that annealing both experimental and geometric nanoparticles results in structures that appear similar in shape and predicted activity, using oxygen adsorption as a measure. Annealing is predicted to increase the catalytic activity in all cases except the truncated octahedra, where it has the opposite effect. As our simulations have been performed with a classical force field, we also assess its suitability to describe the potential energy of such nanoparticles by comparing with large scale density functional theory calculations.

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simulated_annealing_paper - Accepted Manuscript
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Accepted/In Press date: 26 February 2018
e-pub ahead of print date: 16 March 2018

Identifiers

Local EPrints ID: 419697
URI: https://eprints.soton.ac.uk/id/eprint/419697
ISSN: 0953-8984
PURE UUID: 15878d7f-4748-422d-9c2b-e8494c2f4575
ORCID for Chris-Kriton Skylaris: ORCID iD orcid.org/0000-0003-0258-3433

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Date deposited: 19 Apr 2018 16:30
Last modified: 14 Mar 2019 05:09

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Contributors

Author: Tom Ellaby
Author: Jolyon Aarons
Author: Aakash Varambhia
Author: Lewys Jones
Author: Peter D. Nellist
Author: Dogan Ozkaya
Author: Misbah Sarwar
Author: David Thompsett

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