Structural and gas-sensing properties of WO/sub 3/ nanocrystalline powders obtained by a sol-gel method from tungstic acid
2002; IEEE Sensors Council; Volume: 2; Issue: 4 Linguagem: Inglês
10.1109/jsen.2002.803747
ISSN1558-1748
AutoresI. Jiménez, Jordi Arbiol, A. Cornet, J.R. Morante,
Tópico(s)Analytical Chemistry and Sensors
ResumoWO/sub 3/ nanocrystalline powders were obtained from tungstic acid following a sol-gel process. Evolution of structural properties with annealing temperature was studied by X-ray diffraction and Raman spectroscopy. These structural properties were compared with those of WO/sub 3/ nanopowders obtained by the most common process of pyrolysis of ammonium paratungstate, usually used in gas sensors applications. Sol-gel WO/sub 3/ showed a high sensor response to NO/sub 2/ and low response to CO and CH/sub 4/. The response of these sensor devices was compared with that of WO/sub 3/ obtained from pyrolysis, showing the latter a worse sensor response to NO/sub 2/. Influence of operating temperature, humidity, and film thickness on NO/sub 2/ detection was studied in order to improve the sensing conditions to this gas.
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