H2S Sensing Properties of WO3 based Gas Sensor

Semiconductor gas sensors based upon n-type WO3 nanoparticle powder were fabricated and their response from 100 ppb to ppm levels of H2S in air has been investigated. In this study, a low power MEMS based micro-hotplate was employed as the substrate and operated at a constant temperature of 350̊C. Experimental data demonstrate repeatable results across the range of concentrations. The devices have good response and recovery times and importantly excellent stability. Cross-sensitivities towards other reducing gases/VOCs showed that the WO3-based sensors are less sensitive to CO, acetone, H2 and CH4 even at much higher ppm levels.