Investigation of Non-Platinum Group Metal Catalysts for Pure-Water Anion Exchange Membrane Electrolysis
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Date
2023
Authors
Beaudoin, Sarah
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Pure water anion exchange membrane water electrolyzers (AEMWEs) show promise for utilizing renewable energy and non-platinum group metal (non-PGM) catalysts to create clean hydrogen fuel. Being a new technology, AEMWEs lack standardized procedures and materials, limiting reproductivity and expansion. Furthermore, complex interactions between the ionomer and catalyst during the oxygen evolution are not well understood, resulting in a lack of baseline performance and therefore scalability. In the following study, five anodic non-PGM catalysts, alongside current baseline catalyst IrO2, are analyzed for their activity, durability, and restructuring in AEMWE. We found that electronic conductivity plays the most significant role in determining metal oxide catalyst performance in AEMWEs, scaling linearly with increasing electrical conductivity. Co3O4 was found to exhibit high performance and electronic conductivity in AEMWEs, therefore five cobalt oxides were chosen to be further studied in AEMWE systems, focusing on the role of conductivity, OER performance, and durability. The results reveal that conductivity is critical in determining the activity of a catalyst in AEMWE, but that practical ionomer loading causes electronically insulative effects. Further, it was found that catalyst restructuring during operation results in negative ionomer interactions, hindering OER activity and long-term stability.
Description
61 pages
Keywords
electrochemistry, water electrolysis, non-PGM catalysts, hydrogen fuel, sustainable chemistry