Date of Graduation
5-2021
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Chemistry (PhD)
Degree Level
Graduate
Department
Chemistry & Biochemistry
Advisor/Mentor
Ingrid Fritsch
Committee Member
Bill Durham
Second Committee Member
Julie Stenken
Third Committee Member
David Paul
Keywords
Electrochemistry, Nanoparticles, Particle Oxidation, Particle Shape, Single Particle Characterization
Abstract
Nanomaterials have revolutionized science and technology. Their unique properties can be exploited, and nanoparticles are being used as catalysts, antimicrobials, drug delivery vehicles, sensors, and more. However, the fundamental properties of nanomaterials and their interactions with their surrounding environments are still poorly understood. In this work, a single-particle approach was used to observe the effects of capping ligand, surrounding solution, and particle shape on the oxidative process to gain deeper understanding of silver nanoparticle properties. When allowed the opportunity, the particles will adsorb to the electrode surface then oxidize in rapid succession upon electrode activation, regardless of capping ligand as long as the electrolyte and applied potential are appropriate. The presence of potassium chloride encourages the oxidation of polyethylene glycol capped particles at an increasing rate over time, but rarely allows oxidation poly-vinylpyrrolidone capped particles. Instead, these particles are better oxidized to silver oxide either in potassium nitrate at high potentials or under alkaline conditions at lower potentials. Successful oxidation of poly-vinylpyrrolidone capped particles enabled the work to be expanded from spheres to cubes and plates, the shape of which bore no effect on the rate of oxidation to silver chloride. Furthermore, a new method of single particle characterization was developed to improve the accuracy and precision of nanoparticle characterization. By combining redox magnetohydrodynamics with dark field microscopy, silver and gold coated silica particles were successfully sized from a flowing mixture in both forward and reverse directions.
Citation
Sikes, J. (2021). Electrochemical Oxidation of Individual Silver Nanoparticles: Exploring the Effect of Particle Shape, Capping Ligand, Electrolyte, and Potential on the Signal. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/4099