Oxygen sensing and oxide formation: Optimisation and novel X-ray studies
Oxygen sensing and oxide formation: Optimisation and novel X-ray studies
Platinum remains vital for the use of electrochemical devices, therefore, understanding of the reactions which occur at the platinum-solution interface is paramount in continuing to improve gas sensors, as well as fuel cells and electrolysers. The following body of work uses a number of electrochemical techniques and X-ray spectroscopies to investigate the surface processes of platinum in acidic media.
The pH range over which the electrochemical behaviour can be accurately modelled by the Nernst equation, has been extended into highly acidic solutions by employing the Hammett acidity function (H0) in place of pH when working below pH 1. Sulfuric acid and perchloric acid have been investigated. Both the hydrogen region and oxide formation region have been studied, and the comparison between these two potential regions by cyclic voltammetry has produced a method for electrolyte concentration measurements.
A variety of X-ray spectroscopies have been used to provide additional understanding of the oxide formation process on platinum. Conventional X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) have presented a baseline for High Energy Resolution Fluorescence Detection (HERFD)-XANES, which offers higher spectral resolution, and Energy Dispersive EXAFS (EDE), which can measure on much smaller time scales. The surface oxidation and reduction of platinum nanoparticles will be discussed.
Additionally, a statistically designed set of experiments have been presented, investigating five parameters in an industrial gas sensor electrode manufacturing process. Both sensor output measurements and lab based techniques were employed to characterise the electrodes. It was shown that the electrode loading could be reduced without affecting the sensors initial performance, so cheaper electrodes can be used.
University of Southampton
Leach, Andrew, Stephen
eb2fee87-ab58-4a28-9319-529de90d1708
May 2019
Leach, Andrew, Stephen
eb2fee87-ab58-4a28-9319-529de90d1708
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Leach, Andrew, Stephen
(2019)
Oxygen sensing and oxide formation: Optimisation and novel X-ray studies.
University of Southampton, Doctoral Thesis, 157pp.
Record type:
Thesis
(Doctoral)
Abstract
Platinum remains vital for the use of electrochemical devices, therefore, understanding of the reactions which occur at the platinum-solution interface is paramount in continuing to improve gas sensors, as well as fuel cells and electrolysers. The following body of work uses a number of electrochemical techniques and X-ray spectroscopies to investigate the surface processes of platinum in acidic media.
The pH range over which the electrochemical behaviour can be accurately modelled by the Nernst equation, has been extended into highly acidic solutions by employing the Hammett acidity function (H0) in place of pH when working below pH 1. Sulfuric acid and perchloric acid have been investigated. Both the hydrogen region and oxide formation region have been studied, and the comparison between these two potential regions by cyclic voltammetry has produced a method for electrolyte concentration measurements.
A variety of X-ray spectroscopies have been used to provide additional understanding of the oxide formation process on platinum. Conventional X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) have presented a baseline for High Energy Resolution Fluorescence Detection (HERFD)-XANES, which offers higher spectral resolution, and Energy Dispersive EXAFS (EDE), which can measure on much smaller time scales. The surface oxidation and reduction of platinum nanoparticles will be discussed.
Additionally, a statistically designed set of experiments have been presented, investigating five parameters in an industrial gas sensor electrode manufacturing process. Both sensor output measurements and lab based techniques were employed to characterise the electrodes. It was shown that the electrode loading could be reduced without affecting the sensors initial performance, so cheaper electrodes can be used.
Text
Leach Final Thesis for Award
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Published date: May 2019
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Local EPrints ID: 433180
URI: http://eprints.soton.ac.uk/id/eprint/433180
PURE UUID: 1d1060cb-1ab9-4862-b6d1-53d9fff087e5
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Date deposited: 09 Aug 2019 16:30
Last modified: 16 Mar 2024 07:58
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Author:
Andrew, Stephen Leach
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