This work focuses on tracking formic acid adsorption as formate onto polycrystalline
gold and its subsequent catalyzed oxidation to carbon dioxide. Formic acid oxidation is notoriously
dependent on supporting electrolyte composition, a dependency that is little
characterized. Additionally, the mechanism of oxidation is in disagreement in the
literature. As such, the two preceding topics are the primary focus of this work, and
are studied in HClO4 and H2SO4 solutions. Cyclic voltammetry experiments supplemented
by mathematical modelling and fitting of data were used. Solution pH and
adsorption of supporting electrolyte anions onto Au(poly) were very influential factors
in determining formate coverages on Au(poly). This alone explains the effect of
supporting electrolyte on this reaction. The coverage of adsorbed formate was found
to be singularly responsible for determining the rate of formic acid oxidation. This
implies a chemical rate limiting step for oxidation, leaving the oxidation rate constant
independent of potential.
Another segment of this work focuses on the statistical mechanics of lattice gases,
namely the role of sites available for adsorption on the activity. This topic is central
to the modelling of multiple adsorbing species in competition for the same adsorption
sites. Activity for interaction-free lattice gases in the thermodynamic limit was found
to be coverage of adsorbates over coverage of sites available for adsorption. This relationship was exploited to simulate coadsorption of two species, the first obeying the Langmuir isotherm and the second following the hard hexagon isotherm. This system was originally considered as a
possible model for coadsorption of formate and sulfate in H2SO4 solutions, but did
not match with data. / Graduate / 0494 / jstrobl@uvic.ca
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/5118 |
| Date | 24 December 2013 |
| Creators | Strobl, Jonathan Richard |
| Contributors | Harrington, David A. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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