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Development and application of pipet-based electrochemical imaging techniques
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Ebejer, Neil (2012) Development and application of pipet-based electrochemical imaging techniques. PhD thesis, University of Warwick.
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WRAP_THESIS_Ebejer_2012.pdf - Submitted Version Download (5Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b2603242~S1
Abstract
This thesis describes the development of an electrochemical scanned probe
microscope, SECCM, outlining the need for such a development, by highlighting
previous techniques and their limitations. SECCM consists of a double barrel
capillary pulled to small dimensions, filled with electrolyte solution and a redox
mediator of choice, with a QRCE is inserted into each channel. A potential is applied
between the QRCEs, whilst modulating the pipet normal to the surface. The probe is
translated towards the surface and once contact is established, a modulation in the
ion current arises due to the physical oscillation of the probe, which is then used as a
feedback parameter for imaging. The potential at the working electrode substrate is
also controlled. SECCM is introduced using a model test substrate, gold bands on
glass, showing that the probe is able to track topographical features, making
simultaneous electrochemical measurements. Ion conductance measurements
between the two QRCEs, are shown to be sensitive to the nature of the substrate
investigated. The fundamental electrochemical behaviour of CVD graphene and
SWNT is investigated. A multimicroscopy approach is used for CVD graphene
studies, correlating surface structure and activity, deducing heterogeneous electron
transfer kinetics through simulation. The SWNT samples are studied in two different
morphologies: as 3D forests; and, as a 2D network. In the forests, the probe is
positioned at the ends and sidewalls, making spot measurements. The voltammetric
behaviour shows very similar responses, whilst in the network, a nanosized probe is
scanned across the surface, showing relatively uniform activity across an entire tube.
These new insights indicate that SWNTs are highly active electrode materials. The
fabrication and characterisation of SECM-SICM probes, in a straightforward manner
is also presented. These types of probes were found to be ideal for the investigation
of biological samples, being extremely easy and quick to fabricate.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry | ||||
Library of Congress Subject Headings (LCSH): | Electrochemical analysis, Scanning electrochemical microscopy | ||||
Official Date: | September 2012 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Department of Chemistry | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Unwin, Patrick R. | ||||
Extent: | xxviii, 163 leaves : illustrations | ||||
Language: | eng |
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