Epitaxial strain has been shown to produce dramatic changes to the orbital structure in transition metal perovskite oxides and, in turn, the rate of oxygen electrocatalysis therein. Here, epitaxial strain is used to investigate the relationship between surface electronic structure and oxygen electrocatalysis in prototypical fuel cell cathode systems. Combining high‐temperature electrical‐conductivity‐relaxation studies and synchrotron‐based X‐ray absorption spectroscopy studies of La0.5Sr0.5CoO3and La0.8Sr0.2Co0.2Fe0.8O3thin films under varying degrees of epitaxial strain reveals a strong correlation between orbital structure and catalysis rates. In both systems, films under biaxial tensile strain simultaneously exhibit the fastest reaction kinetics and lowest electron occupation in the
Effective integration of perovskite films into devices requires knowledge of their electro‐chemomechanical properties. Raman spectroscopy is an excellent tool for probing such properties as the films' vibrational characteristics couple to the lattice volumetric changes during chemical expansion. While lattice volumetric changes are typically accessed by analyzing Raman shifts as a function of pressure, stress, or temperature, such methods can be impractical for thin films and do not capture information on chemical expansion. An in situ Raman spectroscopy technique using an electrochemical titration cell to change the oxygen nonstoichiometry of a model perovskite film, Sr(Ti,Fe)O3−
- NSF-PAR ID:
- 10460506
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 31
- Issue:
- 33
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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