Water Oxidation on Oxygen-Deficient Barium Titanate

A First-Principles Study

Nina Tymińska, Gang Wu, Michel Dupuis

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We present a study of the effects of oxygen vacancies (Ovac) on the oxygen evolution reaction (OER) on the TiO2-terminated (001) surface of cubic BaTiO3 (cBTO-TiO2) using spin-polarized DFT+U calculations and the standard (cation-based) four proton-coupled-electron-transfer methodology. We find that the excess electrons associated with Ovac's are involved in charge transfer (CT) to the intermediate adsorbate species HO∗, O∗, and HOO∗ and/or new surface oxygen hole states that we identified. The CT is responsible for an increase in these species' binding energies to the oxygen-deficient surface (cBTO-TiO2-x) to an extent consistent with their electronegativity. The much stronger stabilization of HO∗ and O∗ compared to HOO∗ results in an increased overpotential ηOER on the reduced oxide. This result is at odds with experiment that shows a significantly increased efficiency for oxygen-deficient BTO, suggesting that a different mechanism and/or surface must be involved under the experimental conditions. We also identify heretofore unreported HO∗ and O∗ intermediate adsorbate structures whereby these species oxidize the surface and a surface oxygen hole is formed adjacent to the adsorption site. We assign the facile surface oxidation to the 2-fold coordination of the surface oxygen atoms in Ti-O-Ti surface moieties and a resulting low work function.

Original languageEnglish
Pages (from-to)8378-8389
Number of pages12
JournalJournal of Physical Chemistry C
Volume121
Issue number15
DOIs
Publication statusPublished - Apr 20 2017

Fingerprint

Barium titanate
barium
Oxygen
Oxidation
oxidation
Water
oxygen
water
Adsorbates
Charge transfer
charge transfer
Electronegativity
Electrons
Oxygen vacancies
Binding energy
Discrete Fourier transforms
Oxides
Cations
Protons
oxygen atoms

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry

Cite this

Water Oxidation on Oxygen-Deficient Barium Titanate : A First-Principles Study. / Tymińska, Nina; Wu, Gang; Dupuis, Michel.

In: Journal of Physical Chemistry C, Vol. 121, No. 15, 20.04.2017, p. 8378-8389.

Research output: Contribution to journalArticle

@article{a508ad96f52b4eae8979472fdda4e0d6,
title = "Water Oxidation on Oxygen-Deficient Barium Titanate: A First-Principles Study",
abstract = "We present a study of the effects of oxygen vacancies (Ovac) on the oxygen evolution reaction (OER) on the TiO2-terminated (001) surface of cubic BaTiO3 (cBTO-TiO2) using spin-polarized DFT+U calculations and the standard (cation-based) four proton-coupled-electron-transfer methodology. We find that the excess electrons associated with Ovac's are involved in charge transfer (CT) to the intermediate adsorbate species HO∗, O∗, and HOO∗ and/or new surface oxygen hole states that we identified. The CT is responsible for an increase in these species' binding energies to the oxygen-deficient surface (cBTO-TiO2-x) to an extent consistent with their electronegativity. The much stronger stabilization of HO∗ and O∗ compared to HOO∗ results in an increased overpotential ηOER on the reduced oxide. This result is at odds with experiment that shows a significantly increased efficiency for oxygen-deficient BTO, suggesting that a different mechanism and/or surface must be involved under the experimental conditions. We also identify heretofore unreported HO∗ and O∗ intermediate adsorbate structures whereby these species oxidize the surface and a surface oxygen hole is formed adjacent to the adsorption site. We assign the facile surface oxidation to the 2-fold coordination of the surface oxygen atoms in Ti-O-Ti surface moieties and a resulting low work function.",
author = "Nina Tymińska and Gang Wu and Michel Dupuis",
year = "2017",
month = "4",
day = "20",
doi = "10.1021/acs.jpcc.6b12425",
language = "English",
volume = "121",
pages = "8378--8389",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "15",

}

TY - JOUR

T1 - Water Oxidation on Oxygen-Deficient Barium Titanate

T2 - A First-Principles Study

AU - Tymińska, Nina

AU - Wu, Gang

AU - Dupuis, Michel

PY - 2017/4/20

Y1 - 2017/4/20

N2 - We present a study of the effects of oxygen vacancies (Ovac) on the oxygen evolution reaction (OER) on the TiO2-terminated (001) surface of cubic BaTiO3 (cBTO-TiO2) using spin-polarized DFT+U calculations and the standard (cation-based) four proton-coupled-electron-transfer methodology. We find that the excess electrons associated with Ovac's are involved in charge transfer (CT) to the intermediate adsorbate species HO∗, O∗, and HOO∗ and/or new surface oxygen hole states that we identified. The CT is responsible for an increase in these species' binding energies to the oxygen-deficient surface (cBTO-TiO2-x) to an extent consistent with their electronegativity. The much stronger stabilization of HO∗ and O∗ compared to HOO∗ results in an increased overpotential ηOER on the reduced oxide. This result is at odds with experiment that shows a significantly increased efficiency for oxygen-deficient BTO, suggesting that a different mechanism and/or surface must be involved under the experimental conditions. We also identify heretofore unreported HO∗ and O∗ intermediate adsorbate structures whereby these species oxidize the surface and a surface oxygen hole is formed adjacent to the adsorption site. We assign the facile surface oxidation to the 2-fold coordination of the surface oxygen atoms in Ti-O-Ti surface moieties and a resulting low work function.

AB - We present a study of the effects of oxygen vacancies (Ovac) on the oxygen evolution reaction (OER) on the TiO2-terminated (001) surface of cubic BaTiO3 (cBTO-TiO2) using spin-polarized DFT+U calculations and the standard (cation-based) four proton-coupled-electron-transfer methodology. We find that the excess electrons associated with Ovac's are involved in charge transfer (CT) to the intermediate adsorbate species HO∗, O∗, and HOO∗ and/or new surface oxygen hole states that we identified. The CT is responsible for an increase in these species' binding energies to the oxygen-deficient surface (cBTO-TiO2-x) to an extent consistent with their electronegativity. The much stronger stabilization of HO∗ and O∗ compared to HOO∗ results in an increased overpotential ηOER on the reduced oxide. This result is at odds with experiment that shows a significantly increased efficiency for oxygen-deficient BTO, suggesting that a different mechanism and/or surface must be involved under the experimental conditions. We also identify heretofore unreported HO∗ and O∗ intermediate adsorbate structures whereby these species oxidize the surface and a surface oxygen hole is formed adjacent to the adsorption site. We assign the facile surface oxidation to the 2-fold coordination of the surface oxygen atoms in Ti-O-Ti surface moieties and a resulting low work function.

UR - http://www.scopus.com/inward/record.url?scp=85020025218&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85020025218&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.6b12425

DO - 10.1021/acs.jpcc.6b12425

M3 - Article

VL - 121

SP - 8378

EP - 8389

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 15

ER -