TY - JOUR
T1 - Influence of strain on SrFeO3-δ oxidation, reduction, and water dissociation
T2 - Insights from ambient pressure X-ray photoelectron spectroscopy
AU - Stoerzinger, Kelsey A.
AU - Wang, Le
AU - Su, Hongyang
AU - Lee, Kyung Jae
AU - Crumlin, Ethan J.
AU - Du, Yingge
N1 - Publisher Copyright:
© 2020
PY - 2020/10/15
Y1 - 2020/10/15
N2 - The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in their use for energy storage and conversion applications. The formation of surface adsorbates and their impact on oxide electronic structure can be challenging to probe experimentally, particularly for thin films which enable the study of epitaxial strain but have low surface areas. Here we present a detailed study using ambient pressure X-ray photoelectron spectroscopy of the reduction and oxidation of strained SrFeO3-δ, induced by changes in temperature, oxygen partial pressure, and water vapor exposure. We find that in comparison to the oxidized lattice, application of tensile strain promotes the formation of oxygen vacancies at the surface, facilitating the subsequent incorporation of oxygen into the lattice in an oxygen environment. While tensile strain does promote the formation of hydroxyls from water dissociation, the kinetics of this process appear more sluggish than on less-strained surfaces, likely due to a competitive surface interaction with oxygen or bulk absorption of hydroxyl species. These findings relating strain, oxygen vacancies, and surface reactivity yield important insight into the surface functionality of oxides for energy conversion and storage applications.
AB - The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in their use for energy storage and conversion applications. The formation of surface adsorbates and their impact on oxide electronic structure can be challenging to probe experimentally, particularly for thin films which enable the study of epitaxial strain but have low surface areas. Here we present a detailed study using ambient pressure X-ray photoelectron spectroscopy of the reduction and oxidation of strained SrFeO3-δ, induced by changes in temperature, oxygen partial pressure, and water vapor exposure. We find that in comparison to the oxidized lattice, application of tensile strain promotes the formation of oxygen vacancies at the surface, facilitating the subsequent incorporation of oxygen into the lattice in an oxygen environment. While tensile strain does promote the formation of hydroxyls from water dissociation, the kinetics of this process appear more sluggish than on less-strained surfaces, likely due to a competitive surface interaction with oxygen or bulk absorption of hydroxyl species. These findings relating strain, oxygen vacancies, and surface reactivity yield important insight into the surface functionality of oxides for energy conversion and storage applications.
KW - Ambient pressure X-ray photoelectron spectroscopy
KW - Brownmillerite
KW - Hydroxylation
KW - Perovskite
KW - Strain
KW - Strontium ferrite
UR - http://www.scopus.com/inward/record.url?scp=85086504743&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85086504743&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2020.146919
DO - 10.1016/j.apsusc.2020.146919
M3 - Article
AN - SCOPUS:85086504743
SN - 0169-4332
VL - 527
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 146919
ER -