Strain effects in core-shell PtCo nanoparticles: A comparison of experimental observations and computational modelling
Strain effects in core-shell PtCo nanoparticles: A comparison of experimental observations and computational modelling
Strain in Pt nanoalloys induced by the secondary metal has long been suggested as a major contributor to the modification of catalytic properties. Here, we investigate strain in PtCo nanoparticles using a combination of computational modelling and microscopy experiments. We have used a combination of molecular dynamics (MD) and large-scale density functional theory (DFT) for our models, alongside experimental work using annular dark field scanning transmission electron microscopy (ADF-STEM). We have performed extensive validation of the interatomic potential against DFT using a Pt568Co18 nanoparticle. Modelling gives access to 3 dimensional structures that can be compared to the 2D ADF-STEM images, which we use to build an understanding of nanoparticle structure and composition. Strain has been measured for PtCo and pure Pt nanoparticles, with MD annealed models compared to ADF-STEM images. Our analysis was performed on a layer by layer basis, where distinct trends between the Pt and PtCo alloy nanoparticles are observed. To our knowledge, we show for the first time a way in which detailed atomistic simulations can be used to augment and help interpret the results of ADF-STEM strain mapping experiments, which will enhance their use in characterisation towards the development of improved catalysts.
24784-24795
Ellaby, Tom Henry
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Varambhia, Aakash
78a03233-af29-4426-a25e-188e51099fe9
Xiaonan, Luo
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Briquet, Ludovic
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Sarwar, Misbah
ae93ef8f-8a84-4a46-95ac-cd9352c44e56
Ozkaya, Dogan
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Thompsett, David
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Nellist, Peter D.
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Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61
14 November 2020
Ellaby, Tom Henry
7f85bf66-4204-49b1-a388-aff6cea19077
Varambhia, Aakash
78a03233-af29-4426-a25e-188e51099fe9
Xiaonan, Luo
902e9ad9-c7b2-4d08-b314-16eb559dee7c
Briquet, Ludovic
710cd061-6781-4f4e-9a5a-4fb3ca929a00
Sarwar, Misbah
ae93ef8f-8a84-4a46-95ac-cd9352c44e56
Ozkaya, Dogan
d6b30e54-3986-41af-a129-d20c42ff94d7
Thompsett, David
2fba717f-67ed-4999-b400-3c3a0681778f
Nellist, Peter D.
f237015c-a26a-473c-960e-de99f2ef5a2d
Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61
Ellaby, Tom Henry, Varambhia, Aakash, Xiaonan, Luo, Briquet, Ludovic, Sarwar, Misbah, Ozkaya, Dogan, Thompsett, David, Nellist, Peter D. and Skylaris, Chris-Kriton
(2020)
Strain effects in core-shell PtCo nanoparticles: A comparison of experimental observations and computational modelling.
Physical Chemistry Chemical Physics, 2020 (42), .
(doi:10.1039/D0CP04318D).
Abstract
Strain in Pt nanoalloys induced by the secondary metal has long been suggested as a major contributor to the modification of catalytic properties. Here, we investigate strain in PtCo nanoparticles using a combination of computational modelling and microscopy experiments. We have used a combination of molecular dynamics (MD) and large-scale density functional theory (DFT) for our models, alongside experimental work using annular dark field scanning transmission electron microscopy (ADF-STEM). We have performed extensive validation of the interatomic potential against DFT using a Pt568Co18 nanoparticle. Modelling gives access to 3 dimensional structures that can be compared to the 2D ADF-STEM images, which we use to build an understanding of nanoparticle structure and composition. Strain has been measured for PtCo and pure Pt nanoparticles, with MD annealed models compared to ADF-STEM images. Our analysis was performed on a layer by layer basis, where distinct trends between the Pt and PtCo alloy nanoparticles are observed. To our knowledge, we show for the first time a way in which detailed atomistic simulations can be used to augment and help interpret the results of ADF-STEM strain mapping experiments, which will enhance their use in characterisation towards the development of improved catalysts.
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Accepted/In Press date: 19 October 2020
e-pub ahead of print date: 20 October 2020
Published date: 14 November 2020
Additional Information:
Funding Information:
The authors acknowledge the use of the IRIDIS 5 High Performance Computing Facility, and associated support services at the University of Southampton, in the completion of this work. We are grateful for computational support from the UK Materials and Molecular Modelling Hub, which is partially funded by EPSRC (EP/P020194 and EP/T022213/1), and access was obtained via the UKCP consortium and funded by EPSRC grant ref EP/P022030/1. T. E. would also like to thank Johnson Matthey and the EPSRC for financial support in the form of a PhD studentship. The authors also acknowledge use of characterization facilities within the David Cockayne Centre for Electron Microscopy, Department of Materials, University of Oxford and in particular the EPSRC (EP/K040375/1 ‘‘South of England Analytical Electron Microscope’’) and additional instrument provision from the Henry Royce Institute (Grant reference EP/R010145/1). We would like to thank Brian Theobald and Jonathan Sharman from JMTC Sonning for provision of the Pt and PtCo samples.
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© 2020 the Owner Societies.
Identifiers
Local EPrints ID: 444836
URI: http://eprints.soton.ac.uk/id/eprint/444836
ISSN: 1463-9076
PURE UUID: ba9a9f76-0c47-4928-9f64-8ef36e18bb3d
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Date deposited: 06 Nov 2020 17:30
Last modified: 06 Jun 2024 04:16
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Contributors
Author:
Tom Henry Ellaby
Author:
Aakash Varambhia
Author:
Luo Xiaonan
Author:
Ludovic Briquet
Author:
Misbah Sarwar
Author:
Dogan Ozkaya
Author:
David Thompsett
Author:
Peter D. Nellist
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