Correlating Surface Crystal Orientation and Gas Kinetics in Perovskite Oxide Electrodes
نویسندگان
چکیده
Solid–gas interactions at electrode surfaces determine the efficiency of solid-oxide fuel cells and electrolyzers. Here, correlation between surface–gas kinetics crystal orientation perovskite electrodes is studied in model system La0.8Sr0.2Co0.2Fe0.8O3. The gas-exchange are characterized by synthesizing epitaxial half-cell geometries where three single-variant produced [i.e., La0.8Sr0.2Co0.2Fe0.8O3/La0.9Sr0.1Ga0.95Mg0.05O3−δ/SrRuO3/SrTiO3 (001), (110), (111)]. Electrochemical impedance spectroscopy electrical conductivity relaxation measurements reveal a strong surface-orientation dependency kinetics, wherein (111)-oriented exhibit an activity >3-times higher as compared to (001)-oriented surfaces. Oxygen partial pressure ( p O 2 )-dependent electrochemical studies that while have different reaction mechanisms rate-limiting steps same (i.e., charge-transfer diatomic oxygen species). First-principles calculations suggest formation energy vacancies adsorption various influenced surface polarity. Finally, synchrotron-based, ambient-pressure X-ray spectroscopies distinct electronic changes chemistry among orientations. Taken together, thin-film epitaxy provides efficient approach control understand reactivity ultimately demonstrating (111)-surface exhibits high density active sites which leads activity.
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ژورنال
عنوان ژورنال: Advanced Materials
سال: 2021
ISSN: ['1521-4095', '0935-9648']
DOI: https://doi.org/10.1002/adma.202100977