Impact of Sr-Incorporation on Cr Oxidation and Water Dissociation in La(1–        x        )SrxCrO3

Kelsey A. Stoerzinger; Yingge Du; Kyuwook Ihm; Kelvin H.L. Zhang; Jun Cai; J. Trey Diulus; Ryan T. Frederick; Gregory S. Herman; Ethan J. Crumlin; Scott A. Chambers

doi:10.1002/admi.201701363

Impact of Sr-Incorporation on Cr Oxidation and Water Dissociation in La_(1– _x ₎Sr_xCrO₃

Kelsey A. Stoerzinger, Yingge Du, Kyuwook Ihm, Kelvin H.L. Zhang, Jun Cai, J. Trey Diulus, Ryan T. Frederick, Gregory S. Herman, Ethan J. Crumlin, Scott A. Chambers

Research output: Contribution to journal › Article › peer-review

13 Scopus citations

Abstract

The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in material stability and the ability to catalyze reactions. The local change in valence and formation of surface adsorbates affect the oxide electronic structure and chemical reactivity, yet are challenging to probe experimentally. In this paper a detailed study of the oxidation and reduction of Cr in the perovskite oxide family of La_(1– _x ₎Sr_xCrO₃ using ambient pressure X-ray photoelectron spectroscopy is presented. The incorporation of Sr increases the propensity to oxidize at the surface, leading to the presence of Cr⁴⁺ and Cr⁶⁺ principally confined to the top unit cell when in equilibrium with O₂ gas. These acidic sites are readily reduced to Cr³⁺ in equilibrium with H₂O vapor, and the resultant amount of hydroxyls formed from the dissociation of H₂O is directly proportional to the density of surface sites formerly oxidized. The quantification of the redox stability of La_(1– _x ₎Sr_xCrO₃ and the relationship between the extent of oxidation, reduction, and hydroxylation with Sr yield important insight into the surface functionality during electrochemical applications.

Original language	English (US)
Article number	1701363
Journal	Advanced Materials Interfaces
Volume	5
Issue number	6
DOIs	https://doi.org/10.1002/admi.201701363
State	Published - Mar 23 2018
Externally published	Yes

Bibliographical note

Funding Information:
AP-XPS measurements and analysis were supported for K.A.S. by the Linus Pauling Distinguished Postdoctoral Fellowship at Pacific Northwest National Laboratory (PNNL LDRD 69319) and for J.T.D. and R.T.F. by the Semiconductor Research Corporation (Contract No. 2013-OJ-2438.001). The authors thank Dr. Suntharampillai Thevuthasan for assistance with AP-XPS. Film growth and characterization was supported at PNNL by the U.S. Department of Energy, Office of Science, Division of Materials Sciences and Engineering under Award No. 10122. The PNNL work was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national science user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. PNNL is a multiprogram national laboratory operated for DOE by Battelle. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under Contract No. DE-AC02-05CH11231.

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keywords

ambient pressure X-ray photoelectron spectroscopy
chromium oxides
hydroxylation
surface oxidation
surface reduction

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10.1002/admi.201701363

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@article{83fabd022c6d4934bffb19f1b45a4adc,

title = "Impact of Sr-Incorporation on Cr Oxidation and Water Dissociation in La(1– x )SrxCrO3 ",

abstract = "The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in material stability and the ability to catalyze reactions. The local change in valence and formation of surface adsorbates affect the oxide electronic structure and chemical reactivity, yet are challenging to probe experimentally. In this paper a detailed study of the oxidation and reduction of Cr in the perovskite oxide family of La(1– x )SrxCrO3 using ambient pressure X-ray photoelectron spectroscopy is presented. The incorporation of Sr increases the propensity to oxidize at the surface, leading to the presence of Cr4+ and Cr6+ principally confined to the top unit cell when in equilibrium with O2 gas. These acidic sites are readily reduced to Cr3+ in equilibrium with H2O vapor, and the resultant amount of hydroxyls formed from the dissociation of H2O is directly proportional to the density of surface sites formerly oxidized. The quantification of the redox stability of La(1– x )SrxCrO3 and the relationship between the extent of oxidation, reduction, and hydroxylation with Sr yield important insight into the surface functionality during electrochemical applications.",

keywords = "ambient pressure X-ray photoelectron spectroscopy, chromium oxides, hydroxylation, surface oxidation, surface reduction",

author = "Stoerzinger, {Kelsey A.} and Yingge Du and Kyuwook Ihm and Zhang, {Kelvin H.L.} and Jun Cai and Diulus, {J. Trey} and Frederick, {Ryan T.} and Herman, {Gregory S.} and Crumlin, {Ethan J.} and Chambers, {Scott A.}",

note = "Funding Information: AP-XPS measurements and analysis were supported for K.A.S. by the Linus Pauling Distinguished Postdoctoral Fellowship at Pacific Northwest National Laboratory (PNNL LDRD 69319) and for J.T.D. and R.T.F. by the Semiconductor Research Corporation (Contract No. 2013-OJ-2438.001). The authors thank Dr. Suntharampillai Thevuthasan for assistance with AP-XPS. Film growth and characterization was supported at PNNL by the U.S. Department of Energy, Office of Science, Division of Materials Sciences and Engineering under Award No. 10122. The PNNL work was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national science user facility sponsored by the Department of Energy{\textquoteright}s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. PNNL is a multiprogram national laboratory operated for DOE by Battelle. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under Contract No. DE-AC02-05CH11231. Publisher Copyright: {\textcopyright} 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim",

year = "2018",

month = mar,

day = "23",

doi = "10.1002/admi.201701363",

language = "English (US)",

volume = "5",

journal = "Advanced Materials Interfaces",

issn = "2196-7350",

publisher = "John Wiley and Sons Ltd",

number = "6",

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TY - JOUR

T1 - Impact of Sr-Incorporation on Cr Oxidation and Water Dissociation in La(1– x )SrxCrO3

AU - Stoerzinger, Kelsey A.

AU - Du, Yingge

AU - Ihm, Kyuwook

AU - Zhang, Kelvin H.L.

AU - Cai, Jun

AU - Diulus, J. Trey

AU - Frederick, Ryan T.

AU - Herman, Gregory S.

AU - Crumlin, Ethan J.

AU - Chambers, Scott A.

N1 - Funding Information: AP-XPS measurements and analysis were supported for K.A.S. by the Linus Pauling Distinguished Postdoctoral Fellowship at Pacific Northwest National Laboratory (PNNL LDRD 69319) and for J.T.D. and R.T.F. by the Semiconductor Research Corporation (Contract No. 2013-OJ-2438.001). The authors thank Dr. Suntharampillai Thevuthasan for assistance with AP-XPS. Film growth and characterization was supported at PNNL by the U.S. Department of Energy, Office of Science, Division of Materials Sciences and Engineering under Award No. 10122. The PNNL work was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national science user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. PNNL is a multiprogram national laboratory operated for DOE by Battelle. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under Contract No. DE-AC02-05CH11231. Publisher Copyright: © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

PY - 2018/3/23

Y1 - 2018/3/23

N2 - The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in material stability and the ability to catalyze reactions. The local change in valence and formation of surface adsorbates affect the oxide electronic structure and chemical reactivity, yet are challenging to probe experimentally. In this paper a detailed study of the oxidation and reduction of Cr in the perovskite oxide family of La(1– x )SrxCrO3 using ambient pressure X-ray photoelectron spectroscopy is presented. The incorporation of Sr increases the propensity to oxidize at the surface, leading to the presence of Cr4+ and Cr6+ principally confined to the top unit cell when in equilibrium with O2 gas. These acidic sites are readily reduced to Cr3+ in equilibrium with H2O vapor, and the resultant amount of hydroxyls formed from the dissociation of H2O is directly proportional to the density of surface sites formerly oxidized. The quantification of the redox stability of La(1– x )SrxCrO3 and the relationship between the extent of oxidation, reduction, and hydroxylation with Sr yield important insight into the surface functionality during electrochemical applications.

AB - The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in material stability and the ability to catalyze reactions. The local change in valence and formation of surface adsorbates affect the oxide electronic structure and chemical reactivity, yet are challenging to probe experimentally. In this paper a detailed study of the oxidation and reduction of Cr in the perovskite oxide family of La(1– x )SrxCrO3 using ambient pressure X-ray photoelectron spectroscopy is presented. The incorporation of Sr increases the propensity to oxidize at the surface, leading to the presence of Cr4+ and Cr6+ principally confined to the top unit cell when in equilibrium with O2 gas. These acidic sites are readily reduced to Cr3+ in equilibrium with H2O vapor, and the resultant amount of hydroxyls formed from the dissociation of H2O is directly proportional to the density of surface sites formerly oxidized. The quantification of the redox stability of La(1– x )SrxCrO3 and the relationship between the extent of oxidation, reduction, and hydroxylation with Sr yield important insight into the surface functionality during electrochemical applications.

KW - ambient pressure X-ray photoelectron spectroscopy

KW - chromium oxides

KW - hydroxylation

KW - surface oxidation

KW - surface reduction

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DO - 10.1002/admi.201701363

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SN - 2196-7350

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M1 - 1701363

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