Title :
Structural and gas-sensing properties of WO3 nanocrystalline powders obtained by a sol-gel method from tungstic acid
Author :
Jiménez, Ismael ; Arbiol, Jordi ; Cornet, Albert ; Morante, Joan Ramon
Author_Institution :
Departament d´´Electronica, Barcelona Univ., Spain
fDate :
8/1/2002 12:00:00 AM
Abstract :
WO3 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 WO3 nanopowders obtained by the most common process of pyrolysis of ammonium paratungstate, usually used in gas sensors applications. Sol-gel WO3 showed a high sensor response to NO2 and low response to CO and CH4. The response of these sensor devices was compared with that of WO3 obtained from pyrolysis, showing the latter a worse sensor response to NO2. Influence of operating temperature, humidity, and film thickness on NO2 detection was studied in order to improve the sensing conditions to this gas.
Keywords :
Raman spectra; X-ray diffraction; annealing; gas sensors; grain growth; grain size; nanoparticles; powder technology; sol-gel processing; transmission electron microscopy; tungsten compounds; Raman spectra; WO3; X-ray diffraction; annealing temperature; film thickness; gas-sensing properties; grain growth; humidity influence; nanocrystalline powders; nanoparticles; operating temperature; pulverization coating; structural properties; transmission electron microscopy; tungstic acid sol-gel process; Annealing; Gas detectors; Nanoparticles; Powders; Raman scattering; Sensor phenomena and characterization; Spectroscopy; Sputtering; Temperature sensors; X-ray diffraction;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2002.803747
