Browsing by Author "Fawcett, W. R."

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Effects of Adsorbed Ions on Simple Electrode Reactions: Part 1—Reduction of Periodate Ion in the Presence of Toluene-p-sulphonate Anions
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Alias, Kamaruzzaman; Fawcett, W. R.
The influence of adsorbed toluene-p-sulphonate ions on the rate of electroreduction of periodate ions at mercury has been studied as a function of electrode potential and bulk concentration of the adsorbing ions in solutions of constant ionic strength. The ratio of the reduction rate in the presence of adsorbed anions to that in their absence at constant potential was found to be a function of the surface concentration of the adsorbed species independent of electrode potential, bulk concentration of the adsorbing species and their orientation on the electrode surface. An analysis of the decelerating effect of the adsorbed ions in terms of an electrostatic model of the interface which considers discreteness-of-charge effects is presented. The results of the analysis indicate that the reacting anion pairs with non-adsorbed cations in the vicinity of the reaction site before entering the activated state.
Structure of the Mercury/Ethylene Carbonate Interface: Part 3.—Adsorption of Thiourea
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Fawcett, W. R.; Mackey, M. D.
The adsorption of thiourea at mercury from ethylene carbonate solutions containing 0.5 mol dm–3 KPF6 and varying amounts of thiourea has been studied by measuring the differential capacity of the polarisable interface as a function of potential. The data were analysed to obtain the surface excess of thiourea as a function of electrode potential and bulk concentration. The parameters characterising the adsorption isotherm are discussed in terms of the electrostatic model for dipole adsorption by Kir'yanov, Krylov and Damaskin. These parameters are also compared with those obtained previously for the adsorption of thiourea from water, methanol, formamide, and dimethylformamide.
Structure of the Mercury/Ethylene Carbonate Interface: Part 1.—Variation in Double Layer Capacity with the Nature of the Electrolyte
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (3), 1973) Fawcett, W. R.; Mackey, M. D.
Differential capacity-potential data for the mercury/solution interface for various 1-1 electrolyte solutions in ethylene carbonate at 40°C are presented and compared with data obtained with other aprotic solvents. It is shown that ionic specific adsorption is absent in the case of KPF6 solutions, the capacity hump observed at anodic potentials being attributed to reorientation of solvent molecules in the inner layer. Inner layer capacity data for this case are presented and discussed in terms of the statistical mechanical model of the inner layer by Levine, Bell and Smith.