Effect of varying ethanol and water compositions on the acetone sensing properties of WO₃ for application in diabetes mellitus monitoring

Abstract

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 of WO 3 materials which were synthesized by varying water and ethanol ratios using a facile solvothermal method for acetone detection. The gas sensing properties of as-prepared WO 3 were tested on acetone C 7 H 8 , NO 2 , NH 3 , H 2 S and CH 4 under relative humidity. X-ray diffraction patterns show that as-prepared WO 3 samples are mainly composed of monoclinic WO 3 , a phase having relatively high selectivity to acetone. The as-prepared WO 3 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.