A kinetic study on polycrystalline platinum (Pt) in sulphuric acid is presented. An electrochemical kinetic mechanism of Pt oxide reduction and surface oxide structures are proposed. The reduction reaction was studied by cyclic voltammetry (CV) and various potential programs that combine sweep and hold periods by an assembled analog instrumentation. The reduction peak was studied under three surface conditions: same oxide coverage θ and same potential E, different θ and same E, and same θ but different E, to determine the influence of θ and E on the peak potential and peak shape. The double-layer charge measured previously by dynamic electrochemical impedance spectroscopy (dEIS) was used to correct the CV baseline. Differential-equation-based models as a function of θ and E were investigated to simulate the oxide reduction and oxidation, and estimate kinetic parameters. A simple mechanism combining desorption and multi-layer growth mechanisms showed good fit with both the spread-out oxidation peak and the sharp reduction peak. A microscopic surface oxide growth model was proposed to explain the surface oxides reduction mechanism. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/7569 |
| Date | 26 September 2016 |
| Creators | Qile, Geer |
| 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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