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Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions
Electrochemical devices, such as fuel cells and electrolysers, are said to be at the forefront of a renewable energy technology revolution centred on hydrogen as an energy carrier. These devices rely on the chemical reactions of oxygen, namely the oxidation of water to evolve oxygen (oxygen evolu...
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| Format: | Thesis |
| Language: | English |
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Centre for Catalysis Research
2016
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| _version_ | 1867613378299559936 |
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| access_status_str | Open Access |
| author | Mohamed, Rhiyaad |
| author2 | Levecque, Pieter B J |
| author_browse | Levecque, Pieter B J Mohamed, Rhiyaad |
| author_facet | Levecque, Pieter B J Mohamed, Rhiyaad |
| author_sort | Mohamed, Rhiyaad |
| collection | Thesis |
| description | Electrochemical devices, such as fuel cells and electrolysers, are said to be at the forefront of a renewable energy technology revolution centred on hydrogen as an energy carrier. These devices rely on the chemical reactions of oxygen, namely the oxidation of water to evolve oxygen (oxygen evolution reaction, OER) and hydrogen , carried out in electrolyser applications or the reverse reaction, the reduction of oxygen to water (oxygen reduction reaction, ORR) producing electricity in the case of fuel cells . Th e reactions of oxygen are however still hindered by extremely slow reaction kinetics. The resultant low efficiencies and associated high cost of electrocatalysts required hinder the widespread commercial success of these devices. In addition, current state - of - the - art electrocatalyst technologies suffer from severe corrosion during operation, presenting an additional barrier to commercialisation and ultimately delaying the successful implementation of a sustainable hydrogen economy. One primary goal of electrocatalysis research is thus the rational design of new materials with higher efficiencies. The fundamental understanding of the behaviour of the electrocatalyst materials towards these reactions will enable greater strides to be achieved in this area. To date much research has been conducted towards this end, however further progress is still required. This thesis details work towards the understanding of a new generation of electrocatalyst technologies for the OER and ORR. This study particularly explore s the use metal oxide based electrocatalyst materials for the oxygen evolution and reduction r eactions as employed in electrolyser and fuel cell applications respectively. The thesis is divided in two parts focusing individually on the OER and ORR respectively. New theoretical and experimental insight into the understanding of oxide electrocataly sts for the OER are discussed in Part I. Part II explores the ORR by studying metal oxides as both catalysts and catalyst support materials in alkaline and acidic environments respectively. Here the emphasis is placed on activity and durability of oxide ma terials under fuel cell operating conditions. The study confirms the promise of oxide based materials and highlights some of the challenges still present in their development for fuel cell applications. The final chapter presents a summary of the thesis. This study provides important insight and contributes towards the further understanding of the use of metal oxides for the OER and ORR. From this study several interesting and promising results were also obtained which warrant further intensive research and investigation. Directions for future research are discussed. [Please note: the full text of this thesis has been deferred until January 2018] |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/20983 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:35:11.861Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Centre for Catalysis Research |
| publisherStr | Centre for Catalysis Research |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/20983 Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions Mohamed, Rhiyaad Levecque, Pieter B J Fabbri, Emiliana Catalysis Research Chemical Engineering Electrochemical devices, such as fuel cells and electrolysers, are said to be at the forefront of a renewable energy technology revolution centred on hydrogen as an energy carrier. These devices rely on the chemical reactions of oxygen, namely the oxidation of water to evolve oxygen (oxygen evolution reaction, OER) and hydrogen , carried out in electrolyser applications or the reverse reaction, the reduction of oxygen to water (oxygen reduction reaction, ORR) producing electricity in the case of fuel cells . Th e reactions of oxygen are however still hindered by extremely slow reaction kinetics. The resultant low efficiencies and associated high cost of electrocatalysts required hinder the widespread commercial success of these devices. In addition, current state - of - the - art electrocatalyst technologies suffer from severe corrosion during operation, presenting an additional barrier to commercialisation and ultimately delaying the successful implementation of a sustainable hydrogen economy. One primary goal of electrocatalysis research is thus the rational design of new materials with higher efficiencies. The fundamental understanding of the behaviour of the electrocatalyst materials towards these reactions will enable greater strides to be achieved in this area. To date much research has been conducted towards this end, however further progress is still required. This thesis details work towards the understanding of a new generation of electrocatalyst technologies for the OER and ORR. This study particularly explore s the use metal oxide based electrocatalyst materials for the oxygen evolution and reduction r eactions as employed in electrolyser and fuel cell applications respectively. The thesis is divided in two parts focusing individually on the OER and ORR respectively. New theoretical and experimental insight into the understanding of oxide electrocataly sts for the OER are discussed in Part I. Part II explores the ORR by studying metal oxides as both catalysts and catalyst support materials in alkaline and acidic environments respectively. Here the emphasis is placed on activity and durability of oxide ma terials under fuel cell operating conditions. The study confirms the promise of oxide based materials and highlights some of the challenges still present in their development for fuel cell applications. The final chapter presents a summary of the thesis. This study provides important insight and contributes towards the further understanding of the use of metal oxides for the OER and ORR. From this study several interesting and promising results were also obtained which warrant further intensive research and investigation. Directions for future research are discussed. [Please note: the full text of this thesis has been deferred until January 2018] 2016-07-28T12:25:14Z 2016-07-28T12:25:14Z 2016 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/20983 eng Centre for Catalysis Research Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Catalysis Research Chemical Engineering Mohamed, Rhiyaad Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions |
| thesis_degree_str | Doctoral |
| title | Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions |
| title_full | Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions |
| title_fullStr | Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions |
| title_full_unstemmed | Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions |
| title_short | Electrocatalysis of oxide-based materials for the oxygen reduction and evolution reactions |
| title_sort | electrocatalysis of oxide based materials for the oxygen reduction and evolution reactions |
| topic | Catalysis Research Chemical Engineering |
| url | http://hdl.handle.net/11427/20983 |
| work_keys_str_mv | AT mohamedrhiyaad electrocatalysisofoxidebasedmaterialsfortheoxygenreductionandevolutionreactions |