Abstract
RuO2 is a highly active electrocatalyst for the oxygen evolution reaction (OER) but is unstable in acidic environments. Herein we investigate the encapsulation of RuO2 nanoparticles with semipermeable, nanoscopic silicon oxide (SiOx) overlayers as a strategy to improve their stability. SiOx encapsulated RuO2 (SiOx|RuO2) electrodes were prepared by drop-casting RuO2 nanoparticles onto glassy carbon substrates followed by deposition of SiOx overlayers of varying thickness by a room temperature photochemical deposition process. The best-performing SiOx|RuO2 electrodes consisted of 2-3 nm thick SiOx overlayers on top of RuO2 particles and 3-7 nm thick SiOx on the glassy carbon substrate. Such electrodes exhibited lower overpotentials relative to bare RuO2 due to an improved electrochemically active surface area while also demonstrating an ability to retain OER activity over time, especially at higher overpotentials. Surprisingly, it was found that the SiOx coating was unable to prevent Ru dissolution, which was found to be proportional to the charge passed and independent of the presence or thickness of the SiOx coating. Thus, other possible explanations for the improved current retention of SiOx|RuO2 electrodes are discussed, including the influences of the overlayer on bubble dynamics and the stability of the underlying glassy carbon substrate.
Original language | English (US) |
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Article number | 054503 |
Journal | Journal of the Electrochemical Society |
Volume | 170 |
Issue number | 5 |
DOIs | |
State | Published - 2023 |
Funding
This study was made possible by a grant from the Qatar National Research Fund under its National Priorities Research Program award number NPRP12S-0131-190024 and by Shell Global Solutions International B.V. The paper’s contents are solely the responsibility of the authors and do not necessarily represent the official views of the Qatar National Research Fund. We acknowledge the Columbia University Shared Materials Characterization Laboratory for the use of SEM and XPS and Ontario Centre for the Characterization of Advanced Materials (OCCAM) for the use of TEM. We would also like to acknowledge Dr Ngai Yin Yip for providing the goniometer used for contact angle measurements. A.F.B. acknowledges the Earth Institute at Columbia University for a postdoctoral fellowship. J. A. acknowledges the Natural Sciences and Engineering Research Council (NSERC) of Canada for a Vanier Canada Graduate scholarship. D.K. acknowledges funding from the Earth Institute’s Collaborative Research Grant.
Keywords
- coatings
- hydrogen
- oxide encapsulated electrocatalysts
- oxygen evolution reaction
- ruthenium oxide
- silicon oxide
- water electrolysis
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Electrochemistry
- Materials Chemistry