Kang, Minkyung (2017) Single nanoparticle electrochemistry. PhD thesis, University of Warwick.

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Abstract

This thesis presents various pipette-based techniques for resolving the electrochemical activities of single nanoentities (e.g., nanoparticles, NPs) in time and/or space. In particular, the work provides a framework for understanding the (electro)chemistry of single NPs and the development of tools to resolve them temporally and/or spatially. Through the use of the state-of-the-art instrumentation developed by the Warwick Electrochemistry & Interfaces Group (WEIG), electrochemical measurements with a “static” probe (i.e., micro-droplet electrochemical cell) have revealed detailed (temporally-resolved) information on the dynamics of the interaction of colloidal NPs (in solution) with electrode surfaces. Through careful data analysis, and supported by simulations, it has been demonstrated how current-time traces provide information on the physical dynamics of individual NPs on an electrode surface. This regime has been further applied to understand the electrodissolution of individual NPs and has revealed the complexity of the process, through carefully designed experiments and thorough quantitative analysis of large data sets. In addition, through the use of the aforementioned instrumentation, new scanning electrochemical probe microscopy (SEPM) regimes have been developed with a “dynamic” probe, providing spatial resolution. A greatly simplified nanoprobe configuration (i.e., a single channelled probe) has been proposed for simultaneous topography and electrochemical flux mapping at the nanoscale, implemented with a new scanning protocol in scanning ion conductance microscopy (SICM). This was directly applied in tandem with FEM simulations to observe and explain heterogeneities in the ion flux at and around individual catalytic NPs adhered to an inert conductive surface during catalytic turnover conditions with electrochemical activity information on surface heterogeneities at the nanoscale. Finally, to highlight the generalities of the approaches, a new configuration of scanning electrochemical microscopy (SECM) combined with SICM with a double-channelled nanoprobe has been introduced, demonstrating the simultaneous visualisation of topography and uptake rate on a biological entity (cell), which is quantified by finite element method (FEM) simulations. In this configuration the probe is multifunctional, delivering analytes to the cell surface, providing probe positional information and detecting changes in the uptake rate of electroactive molecules across the interface.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Electrochemistry, Nanoparticles -- Measurement, Pipettes, Scanning probe microscopy
Official Date:	September 2017
Dates:	Date Event September 2017 UNSPECIFIED
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Unwin, Patrick R
Sponsors:	University of Warwick
Extent:	xxii,183 leaves : illustrations, charts
Language:	eng

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