Investigation of a Combined Hydrogen and Oxygen Spillover Mechanism for Syngas Electro-Oxidation on Ni/YSZ
Name
J. Electrochem. Soc.-2017-Ong-F32-45.pdf
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1.39 MB
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Adobe PDF
Checksum (MD5)
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Author(s)
Ong, Katherine Mary
Hanna, Jeffrey
Ghoniem, Ahmed F
Date Issued
December 2016
Journal
Journal of The Electrochemical Society
Publisher
The Electrochemical Society
Citation
Ong, K., et al. “Investigation of a Combined Hydrogen and Oxygen Spillover Mechanism for Syngas Electro-Oxidation on Ni/YSZ.” Journal of The Electrochemical Society, vol. 164, no. 2, 2017, pp. F32–45. © 2016 The Authors
Version
Final published version
Abstract
An accurate, comprehensive model for the individual and simultaneous electro-oxidation of H[subscript 2] and CO on Ni-YSZ is necessary to predict SOFC performance for a range of gaseous fuels. A mechanism that combines hydrogen (H) spillover to YSZ with oxygen (O) spillover to nickel is implemented in a previously-validated 1D-MEA model with detailed gas-phase transport and surface reforming kinetics in the anode. This model is then successfully fitted to a wide range of experimental polarization data for fuel mixtures. The H and O spillover pathways are then investigated in depth for two anode fuel mixtures: 20% H[subscript 2] + 80% N2and 20% H[subscript 2]+ 80% CO. Although these studies confirm that H spillover is typically the dominant source of current, they also show that the current produced by O spillover is non-negligible at higher currents. Furthermore, it is observed that H[subscript 2] adsorption to nickel becomes the rate-limiting step at high currents in the hydrogen pathways, while the current produced by O spillover to CO(Ni) is never limited by the rate of CO adsorption. The model is then successfully compared to two independent lower temperature data sets. Together these results demonstrate that it is important to model both spillover pathways on Ni/YSZ and to account for rate-limiting H[subscript 2] adsorption at high currents. Keywords: electro-oxidation, hydrogen spillover, Ni/YSZ, oxygen spillover, SOFC, syngas
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.1149/2.0161702JES
