Abstract
We report measurements of the thermopower and Co K -edge x-ray absorption spectroscopy on bilayer and monolayer (Na,K)x (H2 O)y Co O2-δ. According to the Co K -edge x-ray absorption spectra, the Co oxidation number for bilayer hydrate Na0.33 K0.02 (H2 O)1.33 Co O2-δ is higher than that of monolayer hydrate Na0.07 K0.21 (H2 O)0.63 Co O2-δ with a chemical shift of 3.5 eV, which is in sharp contrast with Co K -edge x-ray absorption spectroscopy and cerimetric titration results for Nax (H2 O)y Co O2-δ, where there is essentially no difference of the oxidation number of Co between bilayer and monolayer sodium cobalt oxyhydrates. According to thermopower analysis, band narrowing is observed when γ- Na0.7 Co O2 is transformed to potassium sodium cobalt oxyhydrates.
| Original language | English |
|---|---|
| Article number | 142509 |
| Journal | Applied Physics Letters |
| Volume | 91 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - 2007 Oct 11 |
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)
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Thermopower and Co K -edge studies of potassium sodium cobalt oxyhydrates Na0.33 K0.02 (H2 O)1.33 Co O2-δ and Na0.07 K0.21 (H2 O)0.63 Co O2-δ. / Liu, Chia-Jyi; Liao, Chia Yuan; Wang, Jung Sheng; Nayak, Pradipta K.; Lin, Zhi Ru; Sheu, Hwo Shuenn.
In: Applied Physics Letters, Vol. 91, No. 14, 142509, 11.10.2007.Research output: Contribution to journal › Article
TY - JOUR
T1 - Thermopower and Co K -edge studies of potassium sodium cobalt oxyhydrates Na0.33 K0.02 (H2 O)1.33 Co O2-δ and Na0.07 K0.21 (H2 O)0.63 Co O2-δ
AU - Liu, Chia-Jyi
AU - Liao, Chia Yuan
AU - Wang, Jung Sheng
AU - Nayak, Pradipta K.
AU - Lin, Zhi Ru
AU - Sheu, Hwo Shuenn
PY - 2007/10/11
Y1 - 2007/10/11
N2 - We report measurements of the thermopower and Co K -edge x-ray absorption spectroscopy on bilayer and monolayer (Na,K)x (H2 O)y Co O2-δ. According to the Co K -edge x-ray absorption spectra, the Co oxidation number for bilayer hydrate Na0.33 K0.02 (H2 O)1.33 Co O2-δ is higher than that of monolayer hydrate Na0.07 K0.21 (H2 O)0.63 Co O2-δ with a chemical shift of 3.5 eV, which is in sharp contrast with Co K -edge x-ray absorption spectroscopy and cerimetric titration results for Nax (H2 O)y Co O2-δ, where there is essentially no difference of the oxidation number of Co between bilayer and monolayer sodium cobalt oxyhydrates. According to thermopower analysis, band narrowing is observed when γ- Na0.7 Co O2 is transformed to potassium sodium cobalt oxyhydrates.
AB - We report measurements of the thermopower and Co K -edge x-ray absorption spectroscopy on bilayer and monolayer (Na,K)x (H2 O)y Co O2-δ. According to the Co K -edge x-ray absorption spectra, the Co oxidation number for bilayer hydrate Na0.33 K0.02 (H2 O)1.33 Co O2-δ is higher than that of monolayer hydrate Na0.07 K0.21 (H2 O)0.63 Co O2-δ with a chemical shift of 3.5 eV, which is in sharp contrast with Co K -edge x-ray absorption spectroscopy and cerimetric titration results for Nax (H2 O)y Co O2-δ, where there is essentially no difference of the oxidation number of Co between bilayer and monolayer sodium cobalt oxyhydrates. According to thermopower analysis, band narrowing is observed when γ- Na0.7 Co O2 is transformed to potassium sodium cobalt oxyhydrates.
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U2 - 10.1063/1.2789786
DO - 10.1063/1.2789786
M3 - Article
AN - SCOPUS:34948908783
VL - 91
JO - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 14
M1 - 142509
ER -