Thesis (Ph. D.)--University of Pennsylvania, 1911.

Thesis (Ph. D.)--University of Pennsylvania, 1902. / Includes bibliographical references.

Thesis (M.Sc.(Chemistry))--University of Pretoria, 2000. / Includes abstract in English and Afrikaans. Includes bibliographical references.

Thesis (Ph. D.)--University of Pennsylvania.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed April 26, 2007). PDF text: 232 p. : ill. UMI publication number: AAT 3230060. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.A.)--Boston University

Redox films are a broad class of electrochemically active films with many potential uses. In the present work, Prussian Blue and carbon coated electrodes have been investigated as possible electrochemical sensors for ascorbic acid and pH, respectively. The potential of Prussian Blue as an optical sensor has also been investigated. In the case of Prussian Blue, it has been discovered that up to 100 monolayers can be systematically deposited on gold electrodes by a new technique that we have called "directed assembly". This provides control of layer thickness with nanometer precision. In the case of carbon coated electrodes, we have developed a mechanical coating technique for quartz crystals, which allows them to be used in electrochemical cells, simultaneously as working electrodes and as mass sensors in a quartz crystal microbalance. This opens up the possibility of developing a variety of new sensor technologies, including pH-sensitive microelectrodes.

No description available.

Methods are presented here for the determination of nitrate by electrochemical techniques. The reaction of nitrate with various organic reagents was studied by differential pulse polarography and a method described based on the nitration of benzoic acid. A rectilinear response was obtained over a 10-6 to 5x10-3M concentration range with reproducibility of < 2% at higher nitrate concentrations.

The electrochemical oxidation and reduction of galena (PbS) was studied in aqueous solutions of perchloric acid between pH 0 and 4. The wide variation of rest potential as reported in the literature was explained on the basis of stoichiometric variations of this material as well as the activities of ionic and molecular species involved in the PbS equilibria. The stoichiometry of the anodic and cathodic reactions was determined to be primarily PbS ↦ Pb⁺⁺+ S° + 2e⁻ and PbS + 2H⁺ + 2e⁻↦ Pb° + H₂S respectively. The irreversibility of anodic oxidation to lead sulphate was observed, with no sulphate produced below about 0.7 to 1.0 volt, depending on the pH. Polarization experiments revealed that ohmic, concentration, and activation polarization effects all contributed to the non-equilibrium behavior of PbS. Reaction of Pb0₂ and MnO₂ with PbS was rapid and interpreted as a "galvanic" effect, relying on the conductivity of the reactants as a necessary condition for its success. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate