Abstract
Changes in the chemical states of the sulfonic groups of Nafion in a model polymer electrolyte fuel cell under an oxygen/hydrogen gas atmosphere were studied using sulfur K-edge XANES spectroscopy. First, the chemical state changes in the sulfonic acid groups of both cathode and anode electrodes due to humidity under oxygen/hydrogen gas flow were observed. Reversible spectral changes ascribed to the hydration and dehydration of the sulfonic acid group were observed at both electrodes. This result is similar to the experimental results obtained without introducing oxygen (helium/hydrogen). On the anode, some of the sulfonic acid groups were decomposed to atomic sulfur adsorbed on platinum (Sad) and the amount increased with time. On the cathode, the formation of Sad was suppressed under the oxygen atmosphere. Next, the effects of oxygen gas introduction onto Sad were examined. Sad was at once formed on both electrodes under dry conditions without an oxygen supply. By supplying oxygen gas, Sad on the cathode disappears. Therefore, the catalyst of the cathode has the ability to recover against the poisoning Sad, while that on the anode accumulates.
| Original language | English |
|---|---|
| Pages (from-to) | 38204-38209 |
| Number of pages | 6 |
| Journal | RSC Advances |
| Volume | 8 |
| Issue number | 67 |
| DOIs | |
| Publication status | Published - 2018 Jan 1 |
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ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)
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Chemical state changes of Nafion in model polymer electrolyte fuel cell under oxygen/hydrogen gas atmosphere observed by S-K XANES spectroscopy. / Isegawa, Kazuhisa; Kim, Daehyun; Kondoh, Hiroshi.
In: RSC Advances, Vol. 8, No. 67, 01.01.2018, p. 38204-38209.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Chemical state changes of Nafion in model polymer electrolyte fuel cell under oxygen/hydrogen gas atmosphere observed by S-K XANES spectroscopy
AU - Isegawa, Kazuhisa
AU - Kim, Daehyun
AU - Kondoh, Hiroshi
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Changes in the chemical states of the sulfonic groups of Nafion in a model polymer electrolyte fuel cell under an oxygen/hydrogen gas atmosphere were studied using sulfur K-edge XANES spectroscopy. First, the chemical state changes in the sulfonic acid groups of both cathode and anode electrodes due to humidity under oxygen/hydrogen gas flow were observed. Reversible spectral changes ascribed to the hydration and dehydration of the sulfonic acid group were observed at both electrodes. This result is similar to the experimental results obtained without introducing oxygen (helium/hydrogen). On the anode, some of the sulfonic acid groups were decomposed to atomic sulfur adsorbed on platinum (Sad) and the amount increased with time. On the cathode, the formation of Sad was suppressed under the oxygen atmosphere. Next, the effects of oxygen gas introduction onto Sad were examined. Sad was at once formed on both electrodes under dry conditions without an oxygen supply. By supplying oxygen gas, Sad on the cathode disappears. Therefore, the catalyst of the cathode has the ability to recover against the poisoning Sad, while that on the anode accumulates.
AB - Changes in the chemical states of the sulfonic groups of Nafion in a model polymer electrolyte fuel cell under an oxygen/hydrogen gas atmosphere were studied using sulfur K-edge XANES spectroscopy. First, the chemical state changes in the sulfonic acid groups of both cathode and anode electrodes due to humidity under oxygen/hydrogen gas flow were observed. Reversible spectral changes ascribed to the hydration and dehydration of the sulfonic acid group were observed at both electrodes. This result is similar to the experimental results obtained without introducing oxygen (helium/hydrogen). On the anode, some of the sulfonic acid groups were decomposed to atomic sulfur adsorbed on platinum (Sad) and the amount increased with time. On the cathode, the formation of Sad was suppressed under the oxygen atmosphere. Next, the effects of oxygen gas introduction onto Sad were examined. Sad was at once formed on both electrodes under dry conditions without an oxygen supply. By supplying oxygen gas, Sad on the cathode disappears. Therefore, the catalyst of the cathode has the ability to recover against the poisoning Sad, while that on the anode accumulates.
UR - http://www.scopus.com/inward/record.url?scp=85057157974&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85057157974&partnerID=8YFLogxK
U2 - 10.1039/c8ra06426a
DO - 10.1039/c8ra06426a
M3 - Article
AN - SCOPUS:85057157974
VL - 8
SP - 38204
EP - 38209
JO - RSC Advances
JF - RSC Advances
SN - 2046-2069
IS - 67
ER -