No description available.

The focus of this study was on the electrochemical synthesis and characterisation of polyaniline-modified electrodes.

1T) may be required to divert heavy charged particles, e.g. Cu+.

D.Phil. / The determination of several physiologically important molecules has been carried out using an oxygen electrode and various oxidase or oxygenase enzymes. The enzymatic reactions are monitored either by measuring the initial rates of oxygen uptake from the medium or by calculating the total amount of oxygen consumed in the reactions. Because of the use of enzymes, the determinations are rapid and sensitive and each one is highly specific. Versatility of analysis can be introduced into the system by suitable choice of the enzyme. Furthermore, the methods are simple, and colour or turbidity does not interfere, thus enabling even whole blood to be used directly as sample material ...

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 167-191). Also available in electronic version. Access restricted to campus users.

No description available.

The work presented in this thesis first characterises a high speed channel flow cell and then applies the system to the electro-reduction of nitromethane in aqueous solution. Potential step transient measurements are carried out with the current-time transients simulated using a model based on the absence of axial diffusion. The excellent agreement between theory and experiment confirms the proposed mass transport model and further demonstrates that the combination of current-time transients recorded using the high speed channel flow cell and numerical simulations provide a powerful tool to access homogeneous rate constants of the order 1 x 10⁶s̄¹. The high speed channel flow cell is then used in combination with a range of complementary electrochemical techniques, numerical modelling, in-situ ESR, single crystal experiments and kinetic isotope measurements to infer a mechanistic scheme for the complex electro-reduction pathway of nitromethane in aqueous solution. Platinum, gold, mercury/copper and mercury/gold electrodes are investigated enabling the most conclusive description of the reduction mechanism to date. The reaction pathway is shown to follow an ECEEE type process with the chemical step proceeding at the electrode surface. The heterogeneous rate constant, k_het, describing the chemical step is calculated for each electrode surface. For platinum in the pH range 7.0 - 9.0 this value is 0.3 ± 0.06 cm s̄¹. For mercury/copper it is 0.18 cm s̄¹, for gold/mercury it is 0.06 cm s̄¹ and for Au it is 0.095 cm s̄¹. Consideration of these values shows a surprising independence of the heterogeneous rate constant on the chemical identity of the surface with all of the values being similar to within less than an order of magnitude. The reason for the apparent paradox of the observed surface indifference of the chemical reaction step is explained by a homogeneous H transfer from the carbon to the oxygen of the nitromethane radical anion, formed form the initial electron transfer step, occurring in the layer of solution immediately adjacent to the electrode solution as shown in the scheme below. The resulting species, ^•CH2 N(OH))ˉ then undergoes a rapid irreversible adsorption to the electrode surface and subsequent transformation to the final product the hydroxylamine, CH₃NHOH. It is proposed that if the energy barrier to the adsorption of ^•CH2 N(OH))ˉ is less than that required for the H atom transfer then the reaction rate will be insensitive to the adsorption step and hence the chemical identity of the electrode. This introduces the concept of a whole new electrochemical process: the surface indifferent electrocatalytic reaction.

The focus of this study was on the electrochemical synthesis and characterisation of polyaniline-modified electrodes.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1912. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed March 17, 2009) Includes bibliographical references.

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1930. / Cover title. From the Transactions of the American Electrochemical Society, vol. LVIII, 1930. Includes bibliographical references.