Abstract
Peroxo-polytungstic acid, formed by the direct reaction of metallic tungsten with hydrogen peroxide, precipitated an amorphous salt with potassium bromide. Decomposing the precipitate at 400-800°C in air yielded white hexagonal potassium tungstate, KxWO3+ x 2 (x=0.3), with lattice parameters of a=7.31 and c=7.65 Å. On the other hand, thermal decomposition in a reducing atmosphere (H2/H2O) at 500°C gave dark blue hexagonal tungsten bronze (HTB), KxWO3, with a=7.38 and c=7.52 Å, which were almost identical to those reported for HTB. It was found that the redox reaction between tungstate and HTB was completely reversible. A porous pellet of the present HTB showed metallic conductivity (≈10 S/cm, at 25°C) under dry conditions. In a wet atmosphere with only slight humidity, however, its conductivity was dramatically reduced. The conductivity was recovered by treating it again in a dry condition.
| Original language | English |
|---|---|
| Pages (from-to) | 211-216 |
| Number of pages | 6 |
| Journal | Solid State Ionics |
| Volume | 59 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - 1993 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Electrochemistry
- Physical and Theoretical Chemistry
- Energy Engineering and Power Technology
- Materials Chemistry
- Condensed Matter Physics
Cite this
Hexagonal tungsten bronze synthesized from potassium peroxo-polytungstate and its electrical properties. / Tsuyumoto, Isao; Kishimoto, Akira; Kudo, Tetsuichi.
In: Solid State Ionics, Vol. 59, No. 3-4, 1993, p. 211-216.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hexagonal tungsten bronze synthesized from potassium peroxo-polytungstate and its electrical properties
AU - Tsuyumoto, Isao
AU - Kishimoto, Akira
AU - Kudo, Tetsuichi
PY - 1993
Y1 - 1993
N2 - Peroxo-polytungstic acid, formed by the direct reaction of metallic tungsten with hydrogen peroxide, precipitated an amorphous salt with potassium bromide. Decomposing the precipitate at 400-800°C in air yielded white hexagonal potassium tungstate, KxWO3+ x 2 (x=0.3), with lattice parameters of a=7.31 and c=7.65 Å. On the other hand, thermal decomposition in a reducing atmosphere (H2/H2O) at 500°C gave dark blue hexagonal tungsten bronze (HTB), KxWO3, with a=7.38 and c=7.52 Å, which were almost identical to those reported for HTB. It was found that the redox reaction between tungstate and HTB was completely reversible. A porous pellet of the present HTB showed metallic conductivity (≈10 S/cm, at 25°C) under dry conditions. In a wet atmosphere with only slight humidity, however, its conductivity was dramatically reduced. The conductivity was recovered by treating it again in a dry condition.
AB - Peroxo-polytungstic acid, formed by the direct reaction of metallic tungsten with hydrogen peroxide, precipitated an amorphous salt with potassium bromide. Decomposing the precipitate at 400-800°C in air yielded white hexagonal potassium tungstate, KxWO3+ x 2 (x=0.3), with lattice parameters of a=7.31 and c=7.65 Å. On the other hand, thermal decomposition in a reducing atmosphere (H2/H2O) at 500°C gave dark blue hexagonal tungsten bronze (HTB), KxWO3, with a=7.38 and c=7.52 Å, which were almost identical to those reported for HTB. It was found that the redox reaction between tungstate and HTB was completely reversible. A porous pellet of the present HTB showed metallic conductivity (≈10 S/cm, at 25°C) under dry conditions. In a wet atmosphere with only slight humidity, however, its conductivity was dramatically reduced. The conductivity was recovered by treating it again in a dry condition.
UR - http://www.scopus.com/inward/record.url?scp=0027542447&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027542447&partnerID=8YFLogxK
U2 - 10.1016/0167-2738(93)90052-5
DO - 10.1016/0167-2738(93)90052-5
M3 - Article
AN - SCOPUS:0027542447
VL - 59
SP - 211
EP - 216
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
IS - 3-4
ER -