About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Thermodynamics of Materials in Extreme Environments
|
| Presentation Title |
Density Functional Theory Modeling on the Positive Effect of H2O in Hydrogen Oxidation Reaction on Perovskite Anode for Solid-oxide Fuel Cells |
| Author(s) |
Yueh-Lin Lee, Qi He, Tao Yang, Wenyuan Li, Wei Li, Liang Ma, Shanshan Hu, Yuhua Duan, Xingbo Liu, Gregory Hackett |
| On-Site Speaker (Planned) |
Yueh-Lin Lee |
| Abstract Scope |
The electrochemical performances of the perovskite Sr2Fe1.5Mo0.5O6-δ (SF1.5M) in dry and humidified H2 are investigated by DFT based thermodynamic modeling, electrical conductivity relaxation (ECR), and electrochemical impedance spectroscopy (EIS) techniques. Both the ECR and EIS measurements indicated promoted electrochemical performances of SF1.5M in humidified H2. The DFT based modeling revealed the nonstoichiometry of SF1.5 (001) BO2 slab models significantly alters the HOR energy landscape and reduces the energy of the plateau intermediate state – the step of H2O plus surface oxygen vacancy formation, which couples with increment of the oxygen chemical potential and decrement of the free electron concentration upon increasing humidity. Furthermore, comparing HOR on the dry surface and on the hydrated surface, the H2O plus surface oxygen vacancy formation energies are lower in the latter case. These factors responsible for the positive effect of humidity on the enhanced HOR activities will be discussed for the perovskite-based SOFC anode materials. |