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Memorial University - Electronic Theses and Dissertations 5
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Document Description
TitleElectrochemical CO2 reduction
AuthorBegum, Afroza, 1975-
DescriptionThesis (Ph.D.)--Memorial University of Newfoundland, 2011. Chemistry
Date2011
Paginationxxxi, 291 leaves : ill. (some col.).
SubjectCarbon dioxide mitigation; Carbon dioxide--Industrial applications; Electrolytic reduction; Electrocatalysis
DegreePh.D.
Degree GrantorMemorial University of Newfoundland. Dept. of Chemistry
DisciplineChemistry
LanguageEng
NotesBibliography: leaves 192-209.
AbstractElectrochemical methods for CO2 reduction have been receiving continuous attention for the last few decades mainly for the conversion of CO2 to fuels as an alternative global energy source and the inexpensive production of carboxylated products for industrial applications. CO2 is considered as a greenhouse gas, whose increasing concentration in the atmosphere is a growing environmental concern. The main obstacle for the direct electrochemical reduction of CO2 is the requirements of very high negative standard potential as high as -2.21 V vs SCE. Several transition-metal based molecular catalysts, for example, ruthenium polypyridyl complexes, were reported to convert CO2 to fuels, such as methanol, formic acid, oxalic acid, methane etc., at a lower cathodic potential. On the other hand, electrocatalytic conversions of CO2 using aromatic ketones were also found to be useful in the syntheses of medicinally useful materials, such as 2-arylpropanoic acids and α-oxocarboxylic acids (as anti-inflammatory drugs), agricultural chemicals and perfumes. A number of monometallic and bimetallic ruthenium benzimidazole and benzothiazole based polypyridyl complexes were synthesized in this work that were found to be operate as electrocatalysts for CO2 reduction at reasonable cathodic potentials. These complexes were characterized by cyclic voltammetry (CV), electronic absorption (UV-Vis) and emission, X-ray diffraction (XRD) techniques. -- Electrolysis of the complexes was performed to reveal their electrocatalytic effect on CO2 reduction. Product analysis by high-performance liquid chromatography (HPLC)/UV-Vis methods revealed that formate and oxalate are detectable in addition to some other products. In this study, it was found that structural variations in the electrocatalyst could influence the activity, however all benzothiazole containing complexes exhibited much higher activities than those of the corresponding benzimidazole complexes. Formate and oxalate were produced and detected at moderately low cathodic overpotentials for [{(bpy)2Ru}2(py2tbtz)]4+. This is an unprecedented result for benzothiazole complexes. In addition, the electrochemical reduction of CO2 by fluorenone-9-one was found to produce 9-hydroxyfluorene and 9-hydroxyfluorene-9-carboxylic acid, in addition to formate and oxalate at a low cathodic overpotential.
TypeText
Resource TypeElectronic thesis or dissertation
FormatImage/jpeg; Application/pdf
SourcePaper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries
RightsThe author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
CollectionElectronic Theses and Dissertations
Scanning StatusCompleted
PDF File(11.70 MB) -- http://collections.mun.ca/PDFs/theses/Begum_Afroza.pdf
CONTENTdm file name14719.cpd