Electrochemical nucleation
Electrochemical nucleation
A study has been made of electrochemical nucleation of metals from aqueous solution. Of principal concern was the electrochemical nucleation of silver on graphite, of silver on platinum and of mercury on graphite.In the first part a survey was made of the existing theories of electrochemical nucleation, of the growth of established nuclei and of the kinetics of nucleation.'The second part is concerned with the results of this research. The experimental work itself was concerned to develop smooth electrodes of good reproducibility. Potentiostatic current-time transients wereIrecordedd using high quality signal generation and. data acquisition systems. These measurements were supplemented by visual observation of the nuclear density. The current-time transients were used to examine existing theories of diffusion-controlled nuclear growth and to determine the number of nuclei as a function of over potential, concentration and, acidity. The potentiostatic double pu13e method was also used in an effort to determine the induction time or time lag for the onset of nucleation.The third part of the thesis is concerned with the adequacy of the existing theories of nuclear growth and inter alia with the general problem of electrode kinetics at small electrodes. Both explicit and implicit.'numerical methods of computer simulation have been developed to deal with these problems and a range of new procedures have been shown to be accurate in this respect. Numerical methods have also been applied to more complex processes where the dimensions of the electrode change progressively with time. This is at the heart of the nucleation work and the 'moving boundary' methods successfully developed here indicate not only that both of the existing analytic descriptions are seriously in error but that the nuclear densities calculated by the new techniques are much closer to those visually observed.
University of Southampton
Gunawardena, Gamini Abeysinghe
1976
Gunawardena, Gamini Abeysinghe
Gunawardena, Gamini Abeysinghe
(1976)
Electrochemical nucleation.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
A study has been made of electrochemical nucleation of metals from aqueous solution. Of principal concern was the electrochemical nucleation of silver on graphite, of silver on platinum and of mercury on graphite.In the first part a survey was made of the existing theories of electrochemical nucleation, of the growth of established nuclei and of the kinetics of nucleation.'The second part is concerned with the results of this research. The experimental work itself was concerned to develop smooth electrodes of good reproducibility. Potentiostatic current-time transients wereIrecordedd using high quality signal generation and. data acquisition systems. These measurements were supplemented by visual observation of the nuclear density. The current-time transients were used to examine existing theories of diffusion-controlled nuclear growth and to determine the number of nuclei as a function of over potential, concentration and, acidity. The potentiostatic double pu13e method was also used in an effort to determine the induction time or time lag for the onset of nucleation.The third part of the thesis is concerned with the adequacy of the existing theories of nuclear growth and inter alia with the general problem of electrode kinetics at small electrodes. Both explicit and implicit.'numerical methods of computer simulation have been developed to deal with these problems and a range of new procedures have been shown to be accurate in this respect. Numerical methods have also been applied to more complex processes where the dimensions of the electrode change progressively with time. This is at the heart of the nucleation work and the 'moving boundary' methods successfully developed here indicate not only that both of the existing analytic descriptions are seriously in error but that the nuclear densities calculated by the new techniques are much closer to those visually observed.
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Published date: 1976
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Local EPrints ID: 458341
URI: http://eprints.soton.ac.uk/id/eprint/458341
PURE UUID: b26fd83f-e9cd-4960-88b3-4262a20bd4ab
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Date deposited: 04 Jul 2022 16:46
Last modified: 04 Jul 2022 16:46
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Author:
Gamini Abeysinghe Gunawardena
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