Citation
Ifkovits, Zachary Philip (2023) Strategies for Enabling Stable and Efficient (Photo)Electrochemical Water Splitting. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/jt8t-w739. https://resolver.caltech.edu/CaltechTHESIS:05132023-220300179
Abstract
The electrolysis of water splits H₂O into its constituent parts, generating H₂ fuel and O₂ as a by-product. Although electrolysis has been known since late 1700s and has a consistently expanding industrial capacity, several barriers still exist to its widespread utilization as a clean method of generating hydrogen for industrial uses or as a grid-scale energy storage chemical. Among these, the materials and costs constraints surrounding the use of precious metal catalysts and expenses associated with balance-of-system costs are of primary importance. In this thesis, the first point is addressed by utilizing earth-abundant catalysts for chemical, electrochemical, and photoelectrochemical water splitting reactions. Specifically, MnySb1-yOx catalysts were synthesized for use as both cerium-mediated chemical water oxidation catalysts and as electrochemical water oxidation catalysts, furthering steps towards removing Ir from industrial electrolysis devices. Addition of Sb was shown to stabilize reactive Mn centers in these configurations, offering enhanced stability over pure Mn oxide catalysts. Reduction of electrolyzer balance-of-system costs were addressed in this thesis through the integration of multiple components of a solar-powered electrolysis system into a single, integrated photoelectrochemical water splitting device. Specifically, electrodeposition conditions were shown to affect the spontaneous mesostructuring of Ni-P hydrogen evolution catalysts on silicon photocathodes, leading to enhanced transmission of light to the semiconductor substrate. Furthermore, Y₂SiO₅ protective layers were shown to mitigate the corrosion of Si photocathodes in alkaline environments, an electrochemical environment known to be destructive towards silicon.
| Item Type: | Thesis (Dissertation (Ph.D.)) | |||||||||
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| Subject Keywords: | Electrolysis, Earth-Abundant Catalysis, Water-Splitting, Photoelectrochemistry | |||||||||
| Degree Grantor: | California Institute of Technology | |||||||||
| Division: | Chemistry and Chemical Engineering | |||||||||
| Major Option: | Chemical Engineering | |||||||||
| Thesis Availability: | Not set | |||||||||
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| Defense Date: | 31 March 2023 | |||||||||
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| Record Number: | CaltechTHESIS:05132023-220300179 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechTHESIS:05132023-220300179 | |||||||||
| DOI: | 10.7907/jt8t-w739 | |||||||||
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| Default Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 15167 | |||||||||
| Collection: | CaltechTHESIS | |||||||||
| Deposited By: | Zachary Ifkovits | |||||||||
| Deposited On: | 23 May 2023 22:42 | |||||||||
| Last Modified: | 08 Nov 2023 00:31 |
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