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Type of Document Dissertation Author Merrill, Matthew D. Author's Email Address merrill@chem.fsu.edu URN etd-09092007-185842 Title Water Electrolysis at the Thermodynamic Limit Degree Doctor of Philosophy Department Chemistry and Biochemistry, Department of Advisory Committee
Advisor Name Title Ralph C. Dougherty Committee Chair Anjaneyulu Krothapali Committee Member Kenneth A. Goldsby Committee Member Nancy L. Greenbaum Committee Member Timothy M. Logan Committee Member Keywords
- Electrochemistry
- Water Electrolysis
- Hydrogen Evolution
- Impedance
- Metal Oxide
- Catalysis
- Transfer Coefficient
- Electrocatalysis
- Iron
- Nickel
- Oxygen Evolution
Date of Defense 2006-12-12 Availability unrestricted Abstract Metal oxide catalysts for alkaline water electrolysis were created through cathodic electrodeposition and the deposition variables were explored. It was discovered that the use of ammonium electrolytes and higher current densities during deposition improved catalytic kinetic performance for the oxygen and hydrogen evolution reactions. A NiFe oxide catalyst was developed with a greater than 99 % ideal charge transfer coefficient for oxygen evolution and a NiV oxide catalyst was developed with a greater than 99.9 % ideal charge transfer coefficient. Combined, the NiFe and NiV catalysts catalyzed water electrolysis at greater than 99 % efficiency below 10 mA/cm^2. The NiFe oxide was characterized as being both highly conductive and highly disordered. NiFe, CoFe, and NiCo oxide oxygen evolution catalytic mechanisms were elucidated with electrochemical impedance spectroscopy. The relationship between the charge transfer coefficient of the Butler-Volmer model and the charge transfer resistance of electrochemical impedance spectroscopy was empirically demonstrated. The distortions of impedance on non-linear systems was demonstrated and discussed.Files
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