TY - JOUR
T1 - Investigation of a Combined Hydrogen and Oxygen Spillover Mechanism for Syngas Electro-Oxidation on Ni/YSZ
AU - Ong, K.
AU - Hanna, J.
AU - Ghoniem, A. F.
N1 - KAUST Repository Item: Exported on 2021-04-05
Acknowledgements: The authors acknowledge the financial support of a grant from the King Abdullah University of Science and Technology (KAUST) that made this work possible.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
PY - 2016/12/6
Y1 - 2016/12/6
N2 - An accurate, comprehensive model for the individual and simultaneous electro-oxidation of H2 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% H2 + 80% N2 and 20% H2 + 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 H2 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 H2 adsorption at high currents.
AB - An accurate, comprehensive model for the individual and simultaneous electro-oxidation of H2 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% H2 + 80% N2 and 20% H2 + 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 H2 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 H2 adsorption at high currents.
UR - http://hdl.handle.net/10754/668511
UR - https://iopscience.iop.org/article/10.1149/2.0161702jes
UR - http://www.scopus.com/inward/record.url?scp=85028472931&partnerID=8YFLogxK
U2 - 10.1149/2.0161702jes
DO - 10.1149/2.0161702jes
M3 - Article
SN - 0013-4651
VL - 164
SP - F32-F45
JO - Journal of The Electrochemical Society
JF - Journal of The Electrochemical Society
IS - 2
ER -
