Unusual decrease in conductivity upon hydration in acceptor doped, microcrystalline ceria

William C. Chueh, Chih Kai Yang, Carol M. Garland, Wei Lai, Sossina M. Haile

Research output: Contribution to journalArticle

  • 16 Citations

Abstract

The impact of hydration on the transport properties of microcrystalline Sm0.15Ce0.85O1.925 has been examined. Dense, polycrystalline samples were obtained by conventional ceramic processing and the grain boundary regions were found, by high resolution transmission electron microscopy, to be free of impurity phases. Impedance spectroscopy measurements were performed over the temperature range 250 to 650 °C under dry, H 2O-saturated, and D2O-saturated synthetic air; and over the temperature range 575 to 650 °C under H2-H2O atmospheres. Under oxidizing conditions humidification by either H2O or D2O caused a substantial increase in the grain boundary resistivity, while leaving the bulk (or grain interior) properties unchanged. This unusual behavior, which was found to be both reversible and reproducible, is interpreted in terms of the space-charge model, which adequately explains all the features of the measured data. It is found that the space-charge potential increases by 5-7 mV under humidification, in turn, exacerbating oxygen vacancy depletion in the space-charge regions and leading to the observed reduction in grain boundary conductivity. It is proposed that the heightened space-charge potential reflects a change in the relative energetics of vacancy creation in the bulk and at the grain boundary interfaces as a result of water uptake into the grain boundary core. Negligible bulk water uptake is detected under both oxidizing and reducing conditions.

LanguageEnglish (US)
Pages6442-6451
Number of pages10
JournalPhysical Chemistry Chemical Physics
Volume13
Issue number14
DOIs
StatePublished - Apr 14 2011

Profile

Cerium compounds
Hydration
hydration
Grain boundaries
Electric space charge
grain boundaries
space charge
conductivity
Water
Oxygen vacancies
High resolution transmission electron microscopy
Transport properties
water
Vacancies
depletion
transport properties
Spectroscopy
impedance
Impurities
ceramics

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)

Cite this

Unusual decrease in conductivity upon hydration in acceptor doped, microcrystalline ceria. / Chueh, William C.; Yang, Chih Kai; Garland, Carol M.; Lai, Wei; Haile, Sossina M.

In: Physical Chemistry Chemical Physics, Vol. 13, No. 14, 14.04.2011, p. 6442-6451.

Research output: Contribution to journalArticle

Chueh, William C. ; Yang, Chih Kai ; Garland, Carol M. ; Lai, Wei ; Haile, Sossina M./ Unusual decrease in conductivity upon hydration in acceptor doped, microcrystalline ceria. In: Physical Chemistry Chemical Physics. 2011 ; Vol. 13, No. 14. pp. 6442-6451
@article{75b0b51b9a0546b8ad4fc80fcf7408ab,
title = "Unusual decrease in conductivity upon hydration in acceptor doped, microcrystalline ceria",
abstract = "The impact of hydration on the transport properties of microcrystalline Sm0.15Ce0.85O1.925 has been examined. Dense, polycrystalline samples were obtained by conventional ceramic processing and the grain boundary regions were found, by high resolution transmission electron microscopy, to be free of impurity phases. Impedance spectroscopy measurements were performed over the temperature range 250 to 650 °C under dry, H 2O-saturated, and D2O-saturated synthetic air; and over the temperature range 575 to 650 °C under H2-H2O atmospheres. Under oxidizing conditions humidification by either H2O or D2O caused a substantial increase in the grain boundary resistivity, while leaving the bulk (or grain interior) properties unchanged. This unusual behavior, which was found to be both reversible and reproducible, is interpreted in terms of the space-charge model, which adequately explains all the features of the measured data. It is found that the space-charge potential increases by 5-7 mV under humidification, in turn, exacerbating oxygen vacancy depletion in the space-charge regions and leading to the observed reduction in grain boundary conductivity. It is proposed that the heightened space-charge potential reflects a change in the relative energetics of vacancy creation in the bulk and at the grain boundary interfaces as a result of water uptake into the grain boundary core. Negligible bulk water uptake is detected under both oxidizing and reducing conditions.",
author = "Chueh, {William C.} and Yang, {Chih Kai} and Garland, {Carol M.} and Wei Lai and Haile, {Sossina M.}",
year = "2011",
month = "4",
day = "14",
doi = "10.1039/c0cp02198a",
language = "English (US)",
volume = "13",
pages = "6442--6451",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "14",

}

TY - JOUR

T1 - Unusual decrease in conductivity upon hydration in acceptor doped, microcrystalline ceria

AU - Chueh,William C.

AU - Yang,Chih Kai

AU - Garland,Carol M.

AU - Lai,Wei

AU - Haile,Sossina M.

PY - 2011/4/14

Y1 - 2011/4/14

N2 - The impact of hydration on the transport properties of microcrystalline Sm0.15Ce0.85O1.925 has been examined. Dense, polycrystalline samples were obtained by conventional ceramic processing and the grain boundary regions were found, by high resolution transmission electron microscopy, to be free of impurity phases. Impedance spectroscopy measurements were performed over the temperature range 250 to 650 °C under dry, H 2O-saturated, and D2O-saturated synthetic air; and over the temperature range 575 to 650 °C under H2-H2O atmospheres. Under oxidizing conditions humidification by either H2O or D2O caused a substantial increase in the grain boundary resistivity, while leaving the bulk (or grain interior) properties unchanged. This unusual behavior, which was found to be both reversible and reproducible, is interpreted in terms of the space-charge model, which adequately explains all the features of the measured data. It is found that the space-charge potential increases by 5-7 mV under humidification, in turn, exacerbating oxygen vacancy depletion in the space-charge regions and leading to the observed reduction in grain boundary conductivity. It is proposed that the heightened space-charge potential reflects a change in the relative energetics of vacancy creation in the bulk and at the grain boundary interfaces as a result of water uptake into the grain boundary core. Negligible bulk water uptake is detected under both oxidizing and reducing conditions.

AB - The impact of hydration on the transport properties of microcrystalline Sm0.15Ce0.85O1.925 has been examined. Dense, polycrystalline samples were obtained by conventional ceramic processing and the grain boundary regions were found, by high resolution transmission electron microscopy, to be free of impurity phases. Impedance spectroscopy measurements were performed over the temperature range 250 to 650 °C under dry, H 2O-saturated, and D2O-saturated synthetic air; and over the temperature range 575 to 650 °C under H2-H2O atmospheres. Under oxidizing conditions humidification by either H2O or D2O caused a substantial increase in the grain boundary resistivity, while leaving the bulk (or grain interior) properties unchanged. This unusual behavior, which was found to be both reversible and reproducible, is interpreted in terms of the space-charge model, which adequately explains all the features of the measured data. It is found that the space-charge potential increases by 5-7 mV under humidification, in turn, exacerbating oxygen vacancy depletion in the space-charge regions and leading to the observed reduction in grain boundary conductivity. It is proposed that the heightened space-charge potential reflects a change in the relative energetics of vacancy creation in the bulk and at the grain boundary interfaces as a result of water uptake into the grain boundary core. Negligible bulk water uptake is detected under both oxidizing and reducing conditions.

UR - http://www.scopus.com/inward/record.url?scp=79952910929&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79952910929&partnerID=8YFLogxK

U2 - 10.1039/c0cp02198a

DO - 10.1039/c0cp02198a

M3 - Article

VL - 13

SP - 6442

EP - 6451

JO - Physical Chemistry Chemical Physics

T2 - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 14

ER -