Applications of electron coupled proton buffers and redox mediators: hydrogen production devices and selective reduction reactions

MacDonald, Lewis Islay Mckee (2018) Applications of electron coupled proton buffers and redox mediators: hydrogen production devices and selective reduction reactions. PhD thesis, University of Glasgow.

Due to Embargo and/or Third Party Copyright restrictions, this thesis is not available in this service.
Printed Thesis Information: https://eleanor.lib.gla.ac.uk/record=b3301839

Abstract

The field of hydrogen production and usage is a large section of the chemical industry. Hydrogen has been used in the energy, pharmaceutical and food industries, where its availability has helped develope a vast number of commodities for society. The challenges faced by science, originate from the H2 production method. Fossil fuel usage means that currently the production of H2 is linked to an unsustainable source. Gaseous hydrogen also has a complexity to its storage and utilisation, which requires the use of specialist equipment.
In this thesis, the challenge of producing hydrogen is approached by using an electron-coupled proton buffer (ECPB) and water electrolysis. Using an ECPB, the drawbacks of current water electrolysis (mixing of gases, slow kinetics of the oxygen evolving side) can be mitigated by separating the hydrogen and oxygen evolving reactions in space and time. The thesis details catalytically evolving hydrogen from a reduced species using earth abundant materials, instead of rare metals, thus providing a path to lowering the costs of a H2 evolving system.
ECPBs in alkaline conditions were investigated as previous work has only been conducted in acidic media. The reason for investigating alkaline water splitting is because it uses cheaper and more abundant materials in its construction. An anthraquinone structure was shown to act as an ECPB under basic conditions by splitting the oxygen and hydrogen evolving reactions in both space and time.
Finally, a redox mediator acted as a liquid electron and proton store for the selective reduction of nitro groups on a variety of nitroarenes. By using a liquid redox mediator, the specialist equipment required to contain gaseous hydrogen is no longer required.
The work herein shows various ways in which hydrogen can be produced and utilised that do not rely on conventional setups. By separating the standard water electrolysis into two parts using an ECPB, the typical drawbacks and requirements of rare metals can be circumvented. Lastly an unconventional but selective and simple transfer hydrogenation reaction has been shown to proceed using a redox mediator acting as an in-situ provider of electrons and protons to a reduction reaction.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Chemistry, energy, hydrogen, POMs, polyoxometalate, catalysts, water, electrolysis, ECPB, nitroarene, reduction, water electrolysis, electrochemistry.
Subjects: Q Science > QD Chemistry
Colleges/Schools: College of Science and Engineering > School of Chemistry
Supervisor's Name: Cronin, Prof. Leroy and Cogdell, Prof. Richard
Date of Award: 2018
Embargo Date: 1 March 2021
Depositing User: Mr Lewis Islay Mckee MacDonald
Unique ID: glathesis:2018-8862
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 02 Mar 2018 10:58
Last Modified: 26 Mar 2018 10:42
URI: http://theses.gla.ac.uk/id/eprint/8862

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