This thesis is concerned with modelling natural convective flows and specifically with their role in electrochemistry. The studies described here demonstrate that many electroanalytical techniques are prone to non-negligible natural convective effects, thus making the standard assumption for purely diffusional mass transport inapplicable. The chosen approach focusses on investigating idealized systems and establishing orders of magnitude for the quantities of interest. The complexity of the observed natural convective flows and their strong dependence on factors such as container geometry serve as compelling arguments for rigorously excluding natural convection in experimental measurements. The text is structured as follows. Chapter 1 introduces the theoretical framework used in the rest of the text and gives an outline of the electrochemical techniques to which the results in later chapters apply. Chapter 2 surveys the literature on natural convection in electrochemistry and emphasizes recent developments. Chapter 3 studies the natural convection induced by the intrinsic heat of an electrochemical reaction, specifically its effect on mass transport in chronoamperometry and cyclic voltammetry. Chapters 4-6 deal exclusively with coupled heat and momentum transport. Chapter 4 considers the thermal convective flows that arise in an idealized cell for scanning electrochemical microscopy (SECM) and the surrounding air under conditions of imperfect thermostating. Chapter 5 is dedicated to thermal convection in an SECM cell that is being thermostated from below through a solid substrate. This chapter demonstrates the influence of the spatial distribution of substrate thermal conductivity on the observed flows and highlights this effect by using a simpler model of the SECM cell than Chapter 4. Chapter 6 investigates the thermal convection in a novel thermostated cell for electrochemical measurements. Chapter 7 contains the main conclusions from the studies described in the thesis. Appendices A, B and C provide additional data for Chapters 3, 5 and 6, respectively.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:757945 |
| Date | January 2018 |
| Creators | Novev, Yavor Kirilov |
| Contributors | Compton, Richard |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:b8badcfd-e376-4ff6-b2da-b8f821871777 |
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