8.5.2 Anomalous Gasochromic Response Behavior in Hydrogen Sensing with Pt/WO3 Film at Low Temperature Range
- Event
- 14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
Nürnberg/Nuremberg, Germany - Chapter
- 8.5 Optical absorbance-based Sensors
- Author(s)
- S. Okazaki, R. Yamasaki, S. Johjima - Yokohama national university (Japan)
- Pages
- 729 - 731
- DOI
- 10.5162/IMCS2012/8.5.2
- ISBN
- 978-3-9813484-2-2
- Price
- free
Abstract
Gasochromic characteristics of sol-gel derived Pt/WO3 film as a hydrogen sensitive material was evaluated at various temperatures in the near-infrared region by optical transmittance measurements. The sensitivity of the film was high and more than 60% transmittance change was observed at room temperature and higher, with 4 % H2/N2 balance gas. The curves may be approximated by exponential response. The response speed was fast and the 63% response time was about 5 sec. at 25 °C. On the other hand, recovery speed was slower than that of the response, suggesting that the recovery process may not be a reverse reaction of the response mechanism. As temperature lowers, the response becomes slower and weaker, yet reasonable response was still observed at 0 °C. However, anomalous response behavior was observed at -40 °C. The behavior may be attributed to the effect of water formed by the recovery reaction.