In situ reflection absorption spectroscopic techniques for the study of electrogenerated species

Bibliographic Details
Main Author:	Zhao, Ming
Language:	English
Published:	Case Western Reserve University School of Graduate Studies / OhioLINK 1993
Subjects:	In situ reflection absorption spectroscopic techniques electrogenerated species
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=case1057154581

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-case10571545812021-08-03T05:31:04Z In situ reflection absorption spectroscopic techniques for the study of electrogenerated species Zhao, Ming In situ reflection absorption spectroscopic techniques electrogenerated species <p>This dissertation focuses on the development of in situ reflection absorption spectroscopic techniques and their applications. In particular, a new technique is described in which the surface of a rotating disk electrode (RDE) is used as a mirror to reflect light in the UV-visible range at a near normal incidence angle to probe quantitatively absorbing species in the diffusion boundary layer under well-defined hydrodynamic conditions. The analysis of static measurements involving the oxidation of Fe(CN)<sub>6</sub><sup>4-</sup> as a model system was found to be in good agreement with the theory based on hydrodynamics and optics. The time evolution of the integrated profile of Fe(CN)<sub>6</sub><sup>3-</sup> species generated at the surface of the RDE by a potential step was also monitored using the same method yielding transient curves in harmony with those predicted by the theory without introducing any adjustable parameters.</p><p>Further extensions of this experimental arrangement to include the application of a sinusoidal voltage of small amplitude to the RDE to modulate the absorptivity of the solution were also examined. All theoretical predictions were verified experimentally using the oxidation of Fe(CN)<sub>6</sub><sup>4-</sup> probe reaction.</p><p>An instrumental arrangement is described for the acquisition of in situ near normal incidence reflection absorption magnetic circular dichroism (MCD) spectra of the electrode surface. The potential modulated MCD of the basal plane of highly oriented pyrolytic graphite in acid electrolytes was examined. The magnitude of the MCD signal as a function of the applied potential increased with the strength of the external magnetic field. MCD spectra have been also recorded of solution-phase cobalt 4,4′,4′′,4′′ sulphonated phthalocyanine in the Co(II) and Co(III) forms. These highly detailed in situ spectra were found to be in agreement with those reported in the literature. In situ Fourier Transform Infrared Reflection Absorption Spectroscopy (FTIRRAS) was used to elucidate mechanistic pathways associated with the reduction of nitrate on Au mediated by Cd-UPD. On the basis of these measurements it was concluded that the electrocatalytic process yields quantitatively solution-phase nitrite as the only detectable product for (H<sup>+</sup>) < (NO<sub>3</sub><sup>-</sup>). The spectral properties of CO adsorbed on nickel electrodes in alkaline solution have also been examined using in situ FTIRRAS. The results show that the voltammetric peak in the first linear scan in the positive direction for Ni(poly)/CO(ads) surfaces is associated with the electrochemical oxidation of bridge-bonded CO to generate solution-phase carbonate as the only detectable product. The stretching frequency of CO shifted toward lower wavenumbers as the coverage of CO was reduced by electrooxidative stripping.</p> 1993 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1057154581 http://rave.ohiolink.edu/etdc/view?acc_num=case1057154581 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	In situ reflection absorption spectroscopic techniques electrogenerated species
spellingShingle	In situ reflection absorption spectroscopic techniques electrogenerated species Zhao, Ming In situ reflection absorption spectroscopic techniques for the study of electrogenerated species
author	Zhao, Ming
author_facet	Zhao, Ming
author_sort	Zhao, Ming
title	In situ reflection absorption spectroscopic techniques for the study of electrogenerated species
title_short	In situ reflection absorption spectroscopic techniques for the study of electrogenerated species
title_full	In situ reflection absorption spectroscopic techniques for the study of electrogenerated species
title_fullStr	In situ reflection absorption spectroscopic techniques for the study of electrogenerated species
title_full_unstemmed	In situ reflection absorption spectroscopic techniques for the study of electrogenerated species
title_sort	in situ reflection absorption spectroscopic techniques for the study of electrogenerated species
publisher	Case Western Reserve University School of Graduate Studies / OhioLINK
publishDate	1993
url	http://rave.ohiolink.edu/etdc/view?acc_num=case1057154581
work_keys_str_mv	AT zhaoming insitureflectionabsorptionspectroscopictechniquesforthestudyofelectrogeneratedspecies
_version_	1719421156353638400

In situ reflection absorption spectroscopic techniques for the study of electrogenerated species

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