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Electrochemistry in thin layers of solution

Citation

Hubbard, Arthur Thornton (1967) Electrochemistry in thin layers of solution. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-09202002-110337

Abstract

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New electrodes for electrochemistry in thin layers of solution have been constructed which are easier to use and give more reproducible data than previous designs. The theory of voltammetry, chronopotentiometry and chronocoulometry in thin layers is derived and verified for simple systems using these electrodes. The particular advantages of the thin layer approach for study of systems in which adsorption of the reactants can occur and for elucidation of the stoichiometry of complicated reactions have been exploited in the present work.

The extent of adsorption of the I[subscript 2] - I[superscript -], CoY[superscript -] - CoY[superscript -2] and FeY[superscript -] - FeY[superscript -2] couples (H[subscript 4]Y = ethylenediaminetetraacetic acid) at platinum electrodes has been determined. About 2 x 10[superscript -9] mole/cm.[superscript 2] of iodide ion or 2 x 10[superscript -9] mole/cm.[superscript 2] of iodide were shown to be adsorbed in a non-electroactive state. An additional 1 x 10[superscript -9] mole/cm[superscript 2] of iodine but no iodide was adsorbed in an electroactive state. About 3.1 x 10[superscript -10] mole/cm[superscript 2] of CoY[superscript -] or 4.7 x 10[superscript -10] mole/cm[superscript 2] of CoY[superscript -2] are adsorbed at bright platinum electrodes. No adsorption of FeY[superscript -] or FeY[superscript -2] was detected.

The stoichiometry of the electrochemical oxidation of PtCl[subscript 4][superscript -2], PtBr[subscript 4][superscript -2] and PtI[subscript 4][superscript -2], and of the electrochemical reduction of PtCl[subscript 6][superscript -2], PtBr[subscript 6][superscript -2] and PtI[subscript 6][superscript -2] and their hydrolysis products has been examined. The effect of acidity and halide concentration on these reactions was investigated. The reduction of PtCl[subscript 6][superscript -2] leads to PtCl[subscript 4][superscript -2] in solutions containing sufficient acid or chloride, but proceeds directly to platinum metal in neutral, chloride-free solutions. The reduction of PtBr[subscript 6][superscript -2] yields PtBr[subscript 4][superscript -2] in 1 F bromide solutions, but proceeds to the metal in either acid or neutral bromide-free solutions. The oxidation of PtCl[subscript 4][superscript -2] in 1 F chloride solutions appears to give a mixture of PtCl[subscript 6][superscript -2] and Pt(OH)[subscript 2]Cl[subscript 4][superscript -2] , whereas the oxidation of PtBr[subscript 4][superscript -2] in 1 F bromide solutions gives simply PtBr[subscript 6][superscript -2]. The products of hydrolysis of PtCl[subscript 6][superscript -2] and PtBr[subscript 6][superscript -2] are more readily reduced than are the parent complexes.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Anson, Fred C.
Thesis Committee:
  • Unknown, Unknown
Defense Date:22 November 1966
Record Number:CaltechETD:etd-09202002-110337
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-09202002-110337
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3648
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:23 Sep 2002
Last Modified:26 Dec 2012 03:01

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