No Cover Image

E-Thesis 240 views 92 downloads

In-situ electrochemical spectroscopy for reaction monitoring / SCOTT RICHARDSON

Swansea University Author: SCOTT RICHARDSON

  • 2025_Richardson_S.final.71055.pdf

    PDF | E-Thesis – open access

    Copyright: the author, Scott Keith Richardson, 2025 Distributed under the terms of a Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0)

    Download (7.47MB)

DOI (Published version): 10.23889/SUThesis.71055

Abstract

The focus of the thesis is on the development and validation of in-situ characterisation techniques for advanced nanoscaled materials such as 2D molybdenum disulphide (MoS2) and methylammonium lead bromide (MAPbBr3) perovskite. The thesis provides three case studies, the third of which involves the...

Full description

Published: Swansea 2025
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Roy, D., and Klinke, C.
URI: https://cronfa.swan.ac.uk/Record/cronfa71055
first_indexed 2025-12-03T10:20:20Z
last_indexed 2025-12-05T09:33:35Z
id cronfa71055
recordtype RisThesis
fullrecord <?xml version="1.0"?><rfc1807><datestamp>2025-12-03T10:23:06.0341648</datestamp><bib-version>v2</bib-version><id>71055</id><entry>2025-12-03</entry><title>In-situ electrochemical spectroscopy for reaction monitoring</title><swanseaauthors><author><sid>6f9b08d0a4be582fd058093409f35d08</sid><firstname>SCOTT</firstname><surname>RICHARDSON</surname><name>SCOTT RICHARDSON</name><active>true</active><ethesisStudent>false</ethesisStudent></author></swanseaauthors><date>2025-12-03</date><abstract>The focus of the thesis is on the development and validation of in-situ characterisation techniques for advanced nanoscaled materials such as 2D molybdenum disulphide (MoS2) and methylammonium lead bromide (MAPbBr3) perovskite. The thesis provides three case studies, the third of which involves the detection of intermediate formation from a Density Functional Theory (DFT) calculated reaction pathway. All case studies involve the use of an in-house designed polyether ether ketone (PEEK) electrochemical cell.The first case study examines the excitonic properties from the transition metal chalcogenides (TMD) compound MoS2. This compound has gained significant importance in catalysis due to the efficient electron transfer facilitated by excitons and trions, particularly in reactions such as the hydrogen evolution reaction (HER). In the study, a demonstration is made of the visualization of trion distributions and their dynamics in electrochemically exfoliated MoS2,within a typical electrochemical cell setup. The measurements consisted of the asymmetric characteristics of trion photoluminescence (PL), its variation with applied voltage, and the influence of the electrical layer during a voltage scan. The forward and reverse voltage scans highlighted that the PL intensity is increasing from the negative to the positive potentials and that a higher concentration of trions is observed at more positive potentials indicating more activity toward the HER. The hyperspectral images (HSI) used for monitoring the trion signal, exhibited significant spatial variations and a strong dependence on the voltage, highlighting the influence of electrical layer formation on the PL from excitons and trions.The second case study is an investigation into the effects of moisture on degradation and the effects of pH on the water-induced degradation of perovskite compound MAPbBr3; conducted using Fluorescence Microscopy and HSI methods. Initial studies had shown and confirmed that moisture in Relative Humidity (RH) environments had little effect on degradation due to the stability of the perovskite lattice to these environments. The application of water in an electrochemical cell environment was then used to determine if the onset of degradation would take place. Experimental observation confirmed this was the case, which then prompted investigation on other environments in the cell that could help alleviate, slow down and retard the rate of the degradation process. Acidic and basic environments were created using a pH range of 3-9 and PL measurements conducted in-situ using HSI methods were made to monitor the degradation process. The measurements showed that basic environments (pH 8-9) lead to rapid degradation of the perovskite, and the lower the pH number, the slower the rate of degradation. Analysis of the PL spectra from the hyperspectral image, demonstrated that the spectral contribution from the thicker region reduced whereas that from the thinner regions remained unchanged which signified preferential degradation of the thicker regions of the perovskite nanoplatelets (NPLs).The third and final case study involved an in situ electrochemical-Raman method that was developed and used to monitor, identify and validate the reaction pathway of amine nitrosations using DFT calculations. All intermediate species formed have been detected using Raman spectra and correlate with the calculated DFT spectra expected in the reaction pathway to the formation of N-nitrosamine products. Sodium nitrite is used as an affordable and readily available nitrosating reagent, which also serves as an electrolyte in the reaction. A different cell setup was used in this study as graphite is used as the working electrode. In conclusion, the three case studies all demonstrated that the use of electrochemical spectroscopy and imaging methods can be used to monitor reactions using an electrochemical cell setup.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>Electrochemical spectroscopy, Raman and PL spectroscopy, 2D nanomaterials, Molybdenum disulphide, Perovskites. Intermediate detection.</keywords><publishedDay>22</publishedDay><publishedMonth>9</publishedMonth><publishedYear>2025</publishedYear><publishedDate>2025-09-22</publishedDate><doi>10.23889/SUThesis.71055</doi><url/><notes/><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Roy, D., and Klinke, C.</supervisor><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><degreesponsorsfunders>Euro funded</degreesponsorsfunders><apcterm/><funders>Euro funded</funders><projectreference/><lastEdited>2025-12-03T10:23:06.0341648</lastEdited><Created>2025-12-03T10:16:28.2143770</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Chemistry</level></path><authors><author><firstname>SCOTT</firstname><surname>RICHARDSON</surname><order>1</order></author></authors><documents><document><filename>71055__35730__1bebe01696ae47b2a4a400646339aa0a.pdf</filename><originalFilename>2025_Richardson_S.final.71055.pdf</originalFilename><uploaded>2025-12-03T10:19:39.2575441</uploaded><type>Output</type><contentLength>7828305</contentLength><contentType>application/pdf</contentType><version>E-Thesis &#x2013; open access</version><cronfaStatus>true</cronfaStatus><documentNotes>Copyright: the author, Scott Keith Richardson, 2025 Distributed under the terms of a Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0)</documentNotes><copyrightCorrect>true</copyrightCorrect><language>eng</language><licence>https://creativecommons.org/licenses/by-sa/4.0/</licence></document></documents><OutputDurs/></rfc1807>
spelling 2025-12-03T10:23:06.0341648 v2 71055 2025-12-03 In-situ electrochemical spectroscopy for reaction monitoring 6f9b08d0a4be582fd058093409f35d08 SCOTT RICHARDSON SCOTT RICHARDSON true false 2025-12-03 The focus of the thesis is on the development and validation of in-situ characterisation techniques for advanced nanoscaled materials such as 2D molybdenum disulphide (MoS2) and methylammonium lead bromide (MAPbBr3) perovskite. The thesis provides three case studies, the third of which involves the detection of intermediate formation from a Density Functional Theory (DFT) calculated reaction pathway. All case studies involve the use of an in-house designed polyether ether ketone (PEEK) electrochemical cell.The first case study examines the excitonic properties from the transition metal chalcogenides (TMD) compound MoS2. This compound has gained significant importance in catalysis due to the efficient electron transfer facilitated by excitons and trions, particularly in reactions such as the hydrogen evolution reaction (HER). In the study, a demonstration is made of the visualization of trion distributions and their dynamics in electrochemically exfoliated MoS2,within a typical electrochemical cell setup. The measurements consisted of the asymmetric characteristics of trion photoluminescence (PL), its variation with applied voltage, and the influence of the electrical layer during a voltage scan. The forward and reverse voltage scans highlighted that the PL intensity is increasing from the negative to the positive potentials and that a higher concentration of trions is observed at more positive potentials indicating more activity toward the HER. The hyperspectral images (HSI) used for monitoring the trion signal, exhibited significant spatial variations and a strong dependence on the voltage, highlighting the influence of electrical layer formation on the PL from excitons and trions.The second case study is an investigation into the effects of moisture on degradation and the effects of pH on the water-induced degradation of perovskite compound MAPbBr3; conducted using Fluorescence Microscopy and HSI methods. Initial studies had shown and confirmed that moisture in Relative Humidity (RH) environments had little effect on degradation due to the stability of the perovskite lattice to these environments. The application of water in an electrochemical cell environment was then used to determine if the onset of degradation would take place. Experimental observation confirmed this was the case, which then prompted investigation on other environments in the cell that could help alleviate, slow down and retard the rate of the degradation process. Acidic and basic environments were created using a pH range of 3-9 and PL measurements conducted in-situ using HSI methods were made to monitor the degradation process. The measurements showed that basic environments (pH 8-9) lead to rapid degradation of the perovskite, and the lower the pH number, the slower the rate of degradation. Analysis of the PL spectra from the hyperspectral image, demonstrated that the spectral contribution from the thicker region reduced whereas that from the thinner regions remained unchanged which signified preferential degradation of the thicker regions of the perovskite nanoplatelets (NPLs).The third and final case study involved an in situ electrochemical-Raman method that was developed and used to monitor, identify and validate the reaction pathway of amine nitrosations using DFT calculations. All intermediate species formed have been detected using Raman spectra and correlate with the calculated DFT spectra expected in the reaction pathway to the formation of N-nitrosamine products. Sodium nitrite is used as an affordable and readily available nitrosating reagent, which also serves as an electrolyte in the reaction. A different cell setup was used in this study as graphite is used as the working electrode. In conclusion, the three case studies all demonstrated that the use of electrochemical spectroscopy and imaging methods can be used to monitor reactions using an electrochemical cell setup. E-Thesis Swansea Electrochemical spectroscopy, Raman and PL spectroscopy, 2D nanomaterials, Molybdenum disulphide, Perovskites. Intermediate detection. 22 9 2025 2025-09-22 10.23889/SUThesis.71055 COLLEGE NANME COLLEGE CODE Swansea University Roy, D., and Klinke, C. Doctoral Ph.D Euro funded Euro funded 2025-12-03T10:23:06.0341648 2025-12-03T10:16:28.2143770 Faculty of Science and Engineering School of Engineering and Applied Sciences - Chemistry SCOTT RICHARDSON 1 71055__35730__1bebe01696ae47b2a4a400646339aa0a.pdf 2025_Richardson_S.final.71055.pdf 2025-12-03T10:19:39.2575441 Output 7828305 application/pdf E-Thesis – open access true Copyright: the author, Scott Keith Richardson, 2025 Distributed under the terms of a Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0) true eng https://creativecommons.org/licenses/by-sa/4.0/
title In-situ electrochemical spectroscopy for reaction monitoring
spellingShingle In-situ electrochemical spectroscopy for reaction monitoring
SCOTT RICHARDSON
title_short In-situ electrochemical spectroscopy for reaction monitoring
title_full In-situ electrochemical spectroscopy for reaction monitoring
title_fullStr In-situ electrochemical spectroscopy for reaction monitoring
title_full_unstemmed In-situ electrochemical spectroscopy for reaction monitoring
title_sort In-situ electrochemical spectroscopy for reaction monitoring
author_id_str_mv 6f9b08d0a4be582fd058093409f35d08
author_id_fullname_str_mv 6f9b08d0a4be582fd058093409f35d08_***_SCOTT RICHARDSON
author SCOTT RICHARDSON
author2 SCOTT RICHARDSON
format E-Thesis
publishDate 2025
institution Swansea University
doi_str_mv 10.23889/SUThesis.71055
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Chemistry{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Chemistry
document_store_str 1
active_str 0
description The focus of the thesis is on the development and validation of in-situ characterisation techniques for advanced nanoscaled materials such as 2D molybdenum disulphide (MoS2) and methylammonium lead bromide (MAPbBr3) perovskite. The thesis provides three case studies, the third of which involves the detection of intermediate formation from a Density Functional Theory (DFT) calculated reaction pathway. All case studies involve the use of an in-house designed polyether ether ketone (PEEK) electrochemical cell.The first case study examines the excitonic properties from the transition metal chalcogenides (TMD) compound MoS2. This compound has gained significant importance in catalysis due to the efficient electron transfer facilitated by excitons and trions, particularly in reactions such as the hydrogen evolution reaction (HER). In the study, a demonstration is made of the visualization of trion distributions and their dynamics in electrochemically exfoliated MoS2,within a typical electrochemical cell setup. The measurements consisted of the asymmetric characteristics of trion photoluminescence (PL), its variation with applied voltage, and the influence of the electrical layer during a voltage scan. The forward and reverse voltage scans highlighted that the PL intensity is increasing from the negative to the positive potentials and that a higher concentration of trions is observed at more positive potentials indicating more activity toward the HER. The hyperspectral images (HSI) used for monitoring the trion signal, exhibited significant spatial variations and a strong dependence on the voltage, highlighting the influence of electrical layer formation on the PL from excitons and trions.The second case study is an investigation into the effects of moisture on degradation and the effects of pH on the water-induced degradation of perovskite compound MAPbBr3; conducted using Fluorescence Microscopy and HSI methods. Initial studies had shown and confirmed that moisture in Relative Humidity (RH) environments had little effect on degradation due to the stability of the perovskite lattice to these environments. The application of water in an electrochemical cell environment was then used to determine if the onset of degradation would take place. Experimental observation confirmed this was the case, which then prompted investigation on other environments in the cell that could help alleviate, slow down and retard the rate of the degradation process. Acidic and basic environments were created using a pH range of 3-9 and PL measurements conducted in-situ using HSI methods were made to monitor the degradation process. The measurements showed that basic environments (pH 8-9) lead to rapid degradation of the perovskite, and the lower the pH number, the slower the rate of degradation. Analysis of the PL spectra from the hyperspectral image, demonstrated that the spectral contribution from the thicker region reduced whereas that from the thinner regions remained unchanged which signified preferential degradation of the thicker regions of the perovskite nanoplatelets (NPLs).The third and final case study involved an in situ electrochemical-Raman method that was developed and used to monitor, identify and validate the reaction pathway of amine nitrosations using DFT calculations. All intermediate species formed have been detected using Raman spectra and correlate with the calculated DFT spectra expected in the reaction pathway to the formation of N-nitrosamine products. Sodium nitrite is used as an affordable and readily available nitrosating reagent, which also serves as an electrolyte in the reaction. A different cell setup was used in this study as graphite is used as the working electrode. In conclusion, the three case studies all demonstrated that the use of electrochemical spectroscopy and imaging methods can be used to monitor reactions using an electrochemical cell setup.
published_date 2025-09-22T05:34:19Z
_version_ 1856987053823098880
score 11.096212

Similar Items