The University of Southampton
University of Southampton Institutional Repository

X-ray absorption spectroscopy and electrochemical studies of Pt-Sn electrocatalysts

X-ray absorption spectroscopy and electrochemical studies of Pt-Sn electrocatalysts
X-ray absorption spectroscopy and electrochemical studies of Pt-Sn electrocatalysts
The addition of a second metal to form bimetallic electrocatalysts offers a means of enhancing electrocatalytic activity through promotional effects. To establish the structure-activity relationship and ascertain details of the promotional mechanism, it is key to characterise the complex structure of bimetallic nanoparticles and acquire molecular-level information regarding the bonding between the adsorbate and the surface.

This thesis focuses on characterising Pt-Sn bimetallic electrocatalysts using X-ray absorption spectroscopy (XAS) and electrochemical measurements. The work starts with Pt3Sn samples containing both SnO2 and alloyed Sn, where the extent of alloying was examined by a variety of techniques. The presence of Sn did promote CO oxidation, but the extent of alloying showed little effects on CO oxidation activity. To deepen understanding of the promotional mechanism, Pt-Sn samples in which the Sn was present exclusively as either SnO2 or as the Pt-Sn alloy were prepared, the structures of which were ascertained by both XAS and other methods. Both SnO2 and alloyed Sn were found to promote CO oxidation mainly via the bifunctional mechanism, but with different active species and redox couples. Whilst a surface hydroxide of SnO2 (SnIV -OH) generated from a SnII/SnIV reversible redox couple was proposed for Pt-SnO2 using cyclic voltammograms, Pt-Sn-OH from water dissociation on surface Pt-Sn* sites was determined for the surface alloyed Sn using in situ XAS. Finally, through the collection of a library of Pt-Sn XAS data, a method for determination of the contraction of the surface atoms of Pt-Sn alloys was derived, with the contraction found to be proportional to the Pt-Sn coordination number.
University of Southampton
Huang, Haoliang
132a8eda-b800-4fa7-9583-6b4306f30247
Huang, Haoliang
132a8eda-b800-4fa7-9583-6b4306f30247
Russell, Andrea
b6b7c748-efc1-4d5d-8a7a-8e4b69396169

Huang, Haoliang (2020) X-ray absorption spectroscopy and electrochemical studies of Pt-Sn electrocatalysts. Doctoral Thesis, 196pp.

Record type: Thesis (Doctoral)

Abstract

The addition of a second metal to form bimetallic electrocatalysts offers a means of enhancing electrocatalytic activity through promotional effects. To establish the structure-activity relationship and ascertain details of the promotional mechanism, it is key to characterise the complex structure of bimetallic nanoparticles and acquire molecular-level information regarding the bonding between the adsorbate and the surface.

This thesis focuses on characterising Pt-Sn bimetallic electrocatalysts using X-ray absorption spectroscopy (XAS) and electrochemical measurements. The work starts with Pt3Sn samples containing both SnO2 and alloyed Sn, where the extent of alloying was examined by a variety of techniques. The presence of Sn did promote CO oxidation, but the extent of alloying showed little effects on CO oxidation activity. To deepen understanding of the promotional mechanism, Pt-Sn samples in which the Sn was present exclusively as either SnO2 or as the Pt-Sn alloy were prepared, the structures of which were ascertained by both XAS and other methods. Both SnO2 and alloyed Sn were found to promote CO oxidation mainly via the bifunctional mechanism, but with different active species and redox couples. Whilst a surface hydroxide of SnO2 (SnIV -OH) generated from a SnII/SnIV reversible redox couple was proposed for Pt-SnO2 using cyclic voltammograms, Pt-Sn-OH from water dissociation on surface Pt-Sn* sites was determined for the surface alloyed Sn using in situ XAS. Finally, through the collection of a library of Pt-Sn XAS data, a method for determination of the contraction of the surface atoms of Pt-Sn alloys was derived, with the contraction found to be proportional to the Pt-Sn coordination number.

Text
Haoliang Huang_PhD_Thesis
Restricted to Repository staff only until 1 March 2022.
Available under License University of Southampton Thesis Licence.
Text
PTD_Thesis_Huang-SIGNED
Restricted to Repository staff only

More information

Published date: October 2020

Identifiers

Local EPrints ID: 447785
URI: http://eprints.soton.ac.uk/id/eprint/447785
PURE UUID: 3b9bc3e9-1aba-4c9e-a0ba-ca5852038979
ORCID for Andrea Russell: ORCID iD orcid.org/0000-0002-8382-6443

Catalogue record

Date deposited: 22 Mar 2021 17:32
Last modified: 23 Mar 2021 02:35

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×