Abstract:
Tungsten oxide based gas sensors have attracted a lot of attention in breath acetone analysis due to
their potential in clinical diagnosis of diabetes. The major problem with this material in sensor
application has been remarkable response to all gases but low selectivity to specific gases. Herein, we
report the gas sensing performance ofWO3 materials which were synthesized by varying water and
ethanol ratios using a facile solvothermal method for acetone detection. The gas sensing properties of
as-preparedWO3 were tested on acetoneC7H8,NO2, NH3,H2S andCH4 under relative humidity.
X-ray diffraction patterns show that as-preparedWO3 samples are mainly composed of monoclinic
WO3, a phase having relatively high selectivity to acetone. The as-preparedWO3 sensors produced
using 51:49 ratio of water: ethanol show an increase in acetone response as the acetone concentration
increases and a decrease in acetone response as the relative humidity increases. The sensor responded
to a very low acetone concentration ranging from 0.5 to 4.5 ppm which is normally found in human
breath. Furthermore, the sensor exhibited high sensitivity and selectivity to low ppm of acetone at
100 °C. On contrary, the sensor showed significantly lower response to other gases tested.
