Near-Ambient Pressure XPS of Higherature Surface Chemistry in Sr2Co2O5 Thin Films

Wesley T. Hong, Kelsey A. Stoerzinger, Ethan J. Crumlin, Eva Mutoro, Hyoungjeen Jeen, Ho Nyung Lee, Yang Shao-Horn

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Transition metal perovskite oxides are promising electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells, but a lack of fundamental understanding of oxide surfaces impedes the rational design of novel catalysts with improved device efficiencies. In particular, understanding the surface chemistry of oxides is essential for controlling both catalytic activity and long-term stability. Thus, elucidating the physical nature of species on perovskite surfaces and their catalytic enhancement would generate new insights in developing oxide electrocatalysts. In this article, we perform near-ambient pressure XPS of model brownmillerite Sr2Co2O5 (SCO) epitaxial thin films with different crystallographic orientations. Detailed analysis of the Co 2p spectra suggests that the films lose oxygen as a function of temperature. Moreover, deconvolution of the O 1s spectra shows distinct behavior for (114)-oriented SCO films compared to (001)-oriented SCO films, where an additional bulk oxygen species is observed. These findings indicate a change to a perovskite-like oxygen chemistry that occurs more easily in (114) SCO than (001) SCO, likely due to the orientation of oxygen vacancy channels out-of-plane with respect to the film surface. This difference in surface chemistry is responsible for the anisotropy of the oxygen surface exchange coefficient of SCO and may contribute to the enhanced ORR kinetics of La0.8Sr0.2CoO3-δ thin films by SCO surface particles observed previously.

Original languageEnglish (US)
Pages (from-to)574-582
Number of pages9
JournalTopics in Catalysis
Issue number5-7
StatePublished - Mar 1 2016
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2016 Springer Science+Business Media New York.


  • Ambient pressure XPS
  • Electrocatalysis
  • Oxygen reduction
  • Solid oxide fuel cells
  • Strontium cobaltite


Dive into the research topics of 'Near-Ambient Pressure XPS of Higherature Surface Chemistry in Sr2Co2O5 Thin Films'. Together they form a unique fingerprint.

Cite this