Hydrothermal synthesis of new compounds with the pyrochlore structure and its application to nitric oxide abatement

Md Hasan Zahir; Kazuyuki Matsuda; Shingo Katayama; Masanobu Awano

doi:10.2109/jcersj.110.963

Hydrothermal synthesis of new compounds with the pyrochlore structure and its application to nitric oxide abatement

Md Hasan Zahir, Kazuyuki Matsuda, Shingo Katayama, Masanobu Awano^*

^*Corresponding author for this work

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

9 Scopus citations

Abstract

Several new compounds with a pyrochlore-type crystal structure have been synthesized by a low-temperature hydrothermal process under N₂ atmosphere using a mixture of nitrate salts. The chemical compositions of the new pyrochlores are represented as (a) Y₂Sn_1.8Cr_0.2O₇, (b) Y_1.8Sm_0.2Sn_1.8Cr_0.2O₈₇, (c) Y_1.8Ce_0.2Sn_1.8 Cr_0.2O₇, (d) Y_1.8Eu_0.2Sn_1.8Cr_0.2O₇, (e) Y₂Zr_1.8Co_0.2O₇, (f) Ba_0.8Y_1.2Sn_1.8Cr_0.2O₇, (g) Ba_0.6Y_1.2Sm_0.2Sn_1.8Cr_0.2O ₇ and (h) Ca_0.8Sm_1.2Sn_1.8Ni_0.2O₇. The Ba- and Ca-containing pyrochlores exhibited excellent spherical morphology with a pure pyrochlore phase structure and were composed of nanometer-sized particles. A- and B-site-doped pyrochlores maintained a fully ordered crystal structure over a wide temperature range. The pyrochlore oxide powders were tested as catalysts for NO_x absorption and reduction by CH₄. NO could be almost completely converted into N₂ using hydrothermally derived pyrochlore oxide catalysts in the absence of oxygen at high temperatures. Rapid absorption of NO into alkali-substituted pyrochlores was effective for NO removal from the gas phase, absorption being significantly accelerated by the presence of oxygen.

Original language	English
Pages (from-to)	963-969
Number of pages	7
Journal	Journal of the Ceramic Society of Japan
Volume	110
Issue number	1287
DOIs	https://doi.org/10.2109/jcersj.110.963
State	Published - Nov 2002
Externally published	Yes

Keywords

Hydrothermal
Morphology
NO absorption
NO reduction
Pyrochlore oxide

ASJC Scopus subject areas

Ceramics and Composites
General Chemistry
Condensed Matter Physics
Materials Chemistry

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10.2109/jcersj.110.963

Cite this

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title = "Hydrothermal synthesis of new compounds with the pyrochlore structure and its application to nitric oxide abatement",

abstract = "Several new compounds with a pyrochlore-type crystal structure have been synthesized by a low-temperature hydrothermal process under N2 atmosphere using a mixture of nitrate salts. The chemical compositions of the new pyrochlores are represented as (a) Y2Sn1.8Cr0.2O7, (b) Y1.8Sm0.2Sn1.8Cr0.2O87, (c) Y1.8Ce0.2Sn1.8 Cr0.2O7, (d) Y1.8Eu0.2Sn1.8Cr0.2O7, (e) Y2Zr1.8Co0.2O7, (f) Ba0.8Y1.2Sn1.8Cr0.2O7, (g) Ba0.6Y1.2Sm0.2Sn1.8Cr0.2O 7 and (h) Ca0.8Sm1.2Sn1.8Ni0.2O7. The Ba- and Ca-containing pyrochlores exhibited excellent spherical morphology with a pure pyrochlore phase structure and were composed of nanometer-sized particles. A- and B-site-doped pyrochlores maintained a fully ordered crystal structure over a wide temperature range. The pyrochlore oxide powders were tested as catalysts for NOx absorption and reduction by CH4. NO could be almost completely converted into N2 using hydrothermally derived pyrochlore oxide catalysts in the absence of oxygen at high temperatures. Rapid absorption of NO into alkali-substituted pyrochlores was effective for NO removal from the gas phase, absorption being significantly accelerated by the presence of oxygen.",

keywords = "Hydrothermal, Morphology, NO absorption, NO reduction, Pyrochlore oxide",

author = "Zahir, {Md Hasan} and Kazuyuki Matsuda and Shingo Katayama and Masanobu Awano",

year = "2002",

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doi = "10.2109/jcersj.110.963",

language = "English",

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journal = "Journal of the Ceramic Society of Japan",

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TY - JOUR

T1 - Hydrothermal synthesis of new compounds with the pyrochlore structure and its application to nitric oxide abatement

AU - Zahir, Md Hasan

AU - Matsuda, Kazuyuki

AU - Katayama, Shingo

AU - Awano, Masanobu

PY - 2002/11

Y1 - 2002/11

N2 - Several new compounds with a pyrochlore-type crystal structure have been synthesized by a low-temperature hydrothermal process under N2 atmosphere using a mixture of nitrate salts. The chemical compositions of the new pyrochlores are represented as (a) Y2Sn1.8Cr0.2O7, (b) Y1.8Sm0.2Sn1.8Cr0.2O87, (c) Y1.8Ce0.2Sn1.8 Cr0.2O7, (d) Y1.8Eu0.2Sn1.8Cr0.2O7, (e) Y2Zr1.8Co0.2O7, (f) Ba0.8Y1.2Sn1.8Cr0.2O7, (g) Ba0.6Y1.2Sm0.2Sn1.8Cr0.2O 7 and (h) Ca0.8Sm1.2Sn1.8Ni0.2O7. The Ba- and Ca-containing pyrochlores exhibited excellent spherical morphology with a pure pyrochlore phase structure and were composed of nanometer-sized particles. A- and B-site-doped pyrochlores maintained a fully ordered crystal structure over a wide temperature range. The pyrochlore oxide powders were tested as catalysts for NOx absorption and reduction by CH4. NO could be almost completely converted into N2 using hydrothermally derived pyrochlore oxide catalysts in the absence of oxygen at high temperatures. Rapid absorption of NO into alkali-substituted pyrochlores was effective for NO removal from the gas phase, absorption being significantly accelerated by the presence of oxygen.

AB - Several new compounds with a pyrochlore-type crystal structure have been synthesized by a low-temperature hydrothermal process under N2 atmosphere using a mixture of nitrate salts. The chemical compositions of the new pyrochlores are represented as (a) Y2Sn1.8Cr0.2O7, (b) Y1.8Sm0.2Sn1.8Cr0.2O87, (c) Y1.8Ce0.2Sn1.8 Cr0.2O7, (d) Y1.8Eu0.2Sn1.8Cr0.2O7, (e) Y2Zr1.8Co0.2O7, (f) Ba0.8Y1.2Sn1.8Cr0.2O7, (g) Ba0.6Y1.2Sm0.2Sn1.8Cr0.2O 7 and (h) Ca0.8Sm1.2Sn1.8Ni0.2O7. The Ba- and Ca-containing pyrochlores exhibited excellent spherical morphology with a pure pyrochlore phase structure and were composed of nanometer-sized particles. A- and B-site-doped pyrochlores maintained a fully ordered crystal structure over a wide temperature range. The pyrochlore oxide powders were tested as catalysts for NOx absorption and reduction by CH4. NO could be almost completely converted into N2 using hydrothermally derived pyrochlore oxide catalysts in the absence of oxygen at high temperatures. Rapid absorption of NO into alkali-substituted pyrochlores was effective for NO removal from the gas phase, absorption being significantly accelerated by the presence of oxygen.

KW - Hydrothermal

KW - Morphology

KW - NO absorption

KW - NO reduction

KW - Pyrochlore oxide

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M3 - Article

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SN - 1882-0743

VL - 110

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EP - 969

JO - Journal of the Ceramic Society of Japan

JF - Journal of the Ceramic Society of Japan

IS - 1287

ER -

Hydrothermal synthesis of new compounds with the pyrochlore structure and its application to nitric oxide abatement

Abstract

Keywords

ASJC Scopus subject areas

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