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Nonlinear Instabilities in Chemical and Electrochemical Systems University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 2017 Nonlinear Instabilities in Chemical and Electrochemical Systems Jeffrey Gordon Bell University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Bell, Jeffrey Gordon, "Nonlinear Instabilities in Chemical and Electrochemical Systems" (2017). Electronic Theses and Dissertations. 5967. https://scholar.uwindsor.ca/etd/5967 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. These documents are made available for personal study and research purposes only, in accordance with the Canadian Copyright Act and the Creative Commons license—CC BY-NC-ND (Attribution, Non-Commercial, No Derivative Works). Under this license, works must always be attributed to the copyright holder (original author), cannot be used for any commercial purposes, and may not be altered. Any other use would require the permission of the copyright holder. Students may inquire about withdrawing their dissertation and/or thesis from this database. For additional inquiries, please contact the repository administrator via email ([email protected]) or by telephone at 519-253-3000ext. 3208. Nonlinear Instabilities in Chemical and Electrochemical Systems By Jeffrey Gordon Bell A Dissertation Submitted to the Faculty of Graduate Studies through the Department of Chemistry and Biochemistry in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy at the University of Windsor Windsor, Ontario, Canada 2017 © 2017 Jeffrey G. Bell Nonlinear Instabilities in Chemical and Electrochemical Systems by Jeffrey Bell APPROVED BY: __________________________________________________ I. Kiss, External Examiner St. Louis University __________________________________________________ J. Yang Earth & Environmental Sciences __________________________________________________ J.R. Green Department of Chemistry & Biochemistry __________________________________________________ R. Schurko Department of Chemistry & Biochemistry __________________________________________________ J. Wang, Advisor Department of Chemistry & Biochemistry April 21, 2017 DECLARATION OF CO-AUTHORSHIP / PREVIOUS PUBLICATION I. Co-Authorship Declaration I hereby declare that this thesis incorporates material that is result of joint research with Dr. James R. Green, who collaborated on two projects, covered in Chapters 2 and 3. In all cases, the key ideas, primary contributions, and experimental designs were performed by the author, and the contribution of the co-author was primarily through performing and analyzing mass spectrometry and NMR spectrometry. I am aware of the University of Windsor Senate Policy on Authorship and I certify that I have properly acknowledged the contribution of other researchers to my thesis, and have obtained written permission from each of the co-author(s) to include the above material(s) in my thesis. I certify that, with the above qualification, this thesis, and the research to which it refers, is the product of my own work. II. Declaration of Previous Publication This thesis includes 6 original papers that have been previously published/submitted for publication in peer reviewed journals, as follows: Thesis Publication title/full citation Publication Chapter status Chapter 2 (a) Nonlinear Dynamical Behavior in the (a) Published Photodecomposition of N-Bromo-1,4-Benzoquinone-4- Imine, J. G. Bell, J. R. Green, and J. Wang, J. Phys. Chem. A, 117, 4545-4550, 2013. (b) Mixed Mode and Sequential Oscillations in the Cerium- (b) Published Bromate-4-Aminophenol Photoreaction, J. G. Bell and J. Wang, Chaos, 23, 033120, 2013. Chapter 3 Complex Reaction Dynamics in the Cerium - Bromate – 2- Published Methyl-1,4-Hydroquinone Photoreaction, J. G. Bell, J. R. Green, and J. Wang, J. Phys. Chem. A, 118, 9795-9800, 2014. Chapter 4 Complex Spatiotemporal Behavior in the Photosensitive Published Ferroin - Bromate – 4-Nitrophenol Reaction, J. G. Bell and J. Wang, J. Phys. Chem. A, 119, 3323-3328, 2015. Chapter 5 Current and Potential Oscillations during the Electro- Published Oxidation of Bromide Ions, J. G. Bell and J. Wang, J. Electroanal. Chem., 754, 133-137, 2015. Chapter 6 Nonlinear Instabilities during the Electrochemical Published Oxidation of Hydroxymethanesulfinate, J. G. Bell and J. Wang, Electrochim. Acta, 222, 678-684, 2016. iii I certify that I have obtained a written permission from the copyright owner(s) to include the above published material(s) in my thesis. I certify that the above material describes work completed during my registration as graduate student at the University of Windsor. I declare that, to the best of my knowledge, my thesis does not infringe upon anyone’s copyright nor violate any proprietary rights and that any ideas, techniques, quotations, or any other material from the work of other people included in my thesis, published or otherwise, are fully acknowledged in accordance with the standard referencing practices. Furthermore, to the extent that I have included copyrighted material that surpasses the bounds of fair dealing within the meaning of the Canada Copyright Act, I certify that I have obtained a written permission from the copyright owner(s) to include such material(s) in my thesis. I declare that this is a true copy of my thesis, including any final revisions, as approved by my thesis committee and the Graduate Studies office, and that this thesis has not been submitted for a higher degree to any other University or Institution. iv ABSTRACT This dissertation focuses on designing and manipulating nonlinear chemical and electrochemical reactions, with the aim of discovering new behaviors as well as gaining insights into their underlying mechanisms. In Chapter 2 the nonlinear behavior of the 4- aminophenol – bromate photoreaction was investigated from two directions. First, a second autocatalytic cycle was introduced through the incorporation of the metal catalyst cerium (IV). It was found that once the autocatalytic cycles were effectively balanced, complexity in the form of mixed mode oscillations was observed in a closed reactor. This dynamic behavior was successfully simulated using a modified model, which qualitatively reproduced the experimental results. It was also found that the precipitate which forms at the onset of the reaction of 4-aminophenol with bromate, N-bromo-1,4- benzoquinone-4-imine, could form a new bromate-based photochemical oscillator. In Chapter 3, the autocatalytic oxidation of 2-methyl-1,4-hydroquinone by acidic bromate lead to the discovery of a new photochemical oscillator. The system was found to be very sensitive to the intensity of illumination supplied, and complexity in the form of sequential oscillations was discovered using either ferroin or cerium (IV) as catalysts. Interestingly, cerium (IV) had a much more profound effect on the dynamical behavior, substantially lengthening the oscillatory period as well as being capable of inducing mixed-mode oscillations. Chapter 4 reports findings on the photosensitive 4-nitrophenol - bromate reaction. Extreme photo-inhibition was found to occur when illumination was supplied to the system whether in a stirred reactor or when being studied in a spatially extended system. Reaction diffusion experiments showed that under certain conditions long lasting complexity in the form of propagation failures took place. v In Chapter 5, oscillations in both current density and potential were observed during the electro-oxidation of bromide ions. Interestingly, mechanistic findings suggest that the oscillations occurring during the oxidation of bromide ions on a platinum electrode belong to the type of oscillator referred to as Capacitance Mediated Positive Differential Resistance oscillator, and is the first solution based system to fit this class. In Chapter 6, the electro-oxidation of two sulfur compounds was seen to display nonlinear behavior. First, the oxidation of hydroxymethanesulfinate leads to oscillations in both current and potential on platinum or gold electrodes. The formation of an inhibiting layer was seen to have a substantial influence on the systems’ ability to support sustained oscillatory behavior. Electrochemical Impedance Spectroscopy showed that the oxidation of hydroxymethanesulfinate fits the class of an HN-NDR type oscillator. The oxidation of methionine only displayed nonlinear behavior on a gold surface, and only when operated under potentiostatic conditions. The oscillations were accompanied by gold dissolution and it was found that the electro-oxidation of methionine belongs to the N-NDR class. Two novel examples of utilizing nonlinear reactions towards application-based research is shown in Chapter 7. Here, the 4-nitrophenol – bromate oscillator is used to fabricate platinum nanoparticles, exploiting the dynamic bromide ion concentration to guide the growth of the noble metal nanocrystals. As an example of using an electrochemical nonlinear reaction, the gold dissolution occurring during the oxidation of methionine was found to lead to the fabrication of a Au nanoparticle modified electrode. This modified electrode was found to be capable of simultaneously detecting both hydroquinone and pyrocatechol in solutions containing both isomers, which is a significant improvement over regular Au electrodes. vi MEMORIAL In loving memory of my father, Gordon W. Bell 1956-2005 vii DEDICATION I dedicate
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