Contrasting the EXAFS obtained under air and H2environments to reveal details of the surface structure of Pt-Sn nanoparticles
Contrasting the EXAFS obtained under air and H2environments to reveal details of the surface structure of Pt-Sn nanoparticles
Understanding the surface structure of bimetallic nanoparticles is crucial for heterogeneous catalysis. Although surface contraction has been established in monometallic systems, less is known for bimetallic systems, especially of nanoparticles. In this work, the bond length contraction on the surface of bimetallic nanoparticles is revealed by XAS in H2at room temperature on dealloyed Pt-Sn nanoparticles, where most Sn atoms were oxidized and segregated to the surface when measured in air. The average Sn-Pt bond length is found to be ∼0.09 Å shorter than observed in the bulk. To ascertain the effect of the Sn location on the decrease of the average bond length, Pt-Sn samples with lower surface-to-bulk Sn ratios than the dealloyed Pt-Sn were studied. The structural information specifically from the surface was extracted from the averaged XAS results using an improved fitting model combining the data measured in H2and in air. Two samples prepared so as to ensure the absence of Sn in the bulk were also studied in the same fashion. The bond length of surface Sn-Pt and the corresponding coordination number obtained in this study show a nearly linear correlation, the origin of which is discussed and attributed to the poor overlap between the Sn 5p orbitals and the available orbitals of the Pt surface atoms.
11738-11745
Huang, Haoliang
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Nassr, Abu Bakr Ahmed Amine
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Celorrio, Verónica
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Gianolio, Diego
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Hardacre, Christopher
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Brett, Dan J.L.
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Russell, Andrea E.
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28 May 2021
Huang, Haoliang
132a8eda-b800-4fa7-9583-6b4306f30247
Nassr, Abu Bakr Ahmed Amine
e7459341-3f6a-4bf0-a54e-5eda1c521649
Celorrio, Verónica
7a8ccfa9-5d90-4502-8008-5e1bb15035c5
Gianolio, Diego
5b316f7d-f314-4337-954e-8c0ce8e38223
Hardacre, Christopher
0715f59a-c82e-4844-a9f8-6a06fb36320f
Brett, Dan J.L.
652e18b5-dad8-4dc4-bed4-9810052ad27b
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Huang, Haoliang, Nassr, Abu Bakr Ahmed Amine, Celorrio, Verónica, Gianolio, Diego, Hardacre, Christopher, Brett, Dan J.L. and Russell, Andrea E.
(2021)
Contrasting the EXAFS obtained under air and H2environments to reveal details of the surface structure of Pt-Sn nanoparticles.
Physical Chemistry Chemical Physics, 23 (20), .
(doi:10.1039/d1cp00979f).
Abstract
Understanding the surface structure of bimetallic nanoparticles is crucial for heterogeneous catalysis. Although surface contraction has been established in monometallic systems, less is known for bimetallic systems, especially of nanoparticles. In this work, the bond length contraction on the surface of bimetallic nanoparticles is revealed by XAS in H2at room temperature on dealloyed Pt-Sn nanoparticles, where most Sn atoms were oxidized and segregated to the surface when measured in air. The average Sn-Pt bond length is found to be ∼0.09 Å shorter than observed in the bulk. To ascertain the effect of the Sn location on the decrease of the average bond length, Pt-Sn samples with lower surface-to-bulk Sn ratios than the dealloyed Pt-Sn were studied. The structural information specifically from the surface was extracted from the averaged XAS results using an improved fitting model combining the data measured in H2and in air. Two samples prepared so as to ensure the absence of Sn in the bulk were also studied in the same fashion. The bond length of surface Sn-Pt and the corresponding coordination number obtained in this study show a nearly linear correlation, the origin of which is discussed and attributed to the poor overlap between the Sn 5p orbitals and the available orbitals of the Pt surface atoms.
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d1cp00979f (2)
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Accepted/In Press date: 29 April 2021
e-pub ahead of print date: 11 May 2021
Published date: 28 May 2021
Additional Information:
Funding Information:
The UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC (Portfolio Grants EP/K014706/ 2, EP/K014668/1, EP/K014854/1, EP/K014714/1, and EP/I019693/ 1). XAS data were collected at Diamond on B18 as part of the UK Catalysis Hub BAG allocation (SP10306 and SP19850-4). HH acknowledges Fellowship support from the China Scholarship Council (201608440295) and the University of Southampton.
Funding Information:
The UK Catalysis Hub is kindly thanked for resources and support providedviaour membership of the UK Catalysis Hub Consortium and funded by EPSRC (Portfolio Grants EP/K014706/2, EP/K014668/1, EP/K014854/1, EP/K014714/1, and EP/I019693/1). XAS data were collected at Diamond on B18 as part of the UK Catalysis Hub BAG allocation (SP10306 and SP19850-4). HH acknowledges Fellowship support from the China Scholarship Council (201608440295) and the University of Southampton.
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© the Owner Societies 2021.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Identifiers
Local EPrints ID: 450417
URI: http://eprints.soton.ac.uk/id/eprint/450417
ISSN: 1463-9076
PURE UUID: 1a6afcb9-72af-462c-b963-04e578b5f1dd
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Date deposited: 27 Jul 2021 17:25
Last modified: 06 Jun 2024 01:37
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Contributors
Author:
Haoliang Huang
Author:
Abu Bakr Ahmed Amine Nassr
Author:
Verónica Celorrio
Author:
Diego Gianolio
Author:
Christopher Hardacre
Author:
Dan J.L. Brett
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