H2S Gas Sensor Based on WO3 Nanostructures Synthesized via Aerosol Assisted Chemical Vapor Deposition Technique

Herein we demonstrate tungsten oxide (WO3) nanostructures based resistive type sensors for hydrogen sulfide (H2S) gas sensing utility. The WO3 dynamic layers have been deposited upon alumina substrates pre-patterned with gold (Au) interdigitated electrodes. For comparative study, two distinct WO3 nanostructures (S-425 and S-450) have been synthesized using Aerosol Assisted Chemical Vapor Deposition (AACVD) technique at varied deposition temperatures i.e., 425 and 450 degrees C, respectively. The gas detecting properties of both sensors were investigated against varied concentration (0-60 ppm) of H2S gas levels. The electrical resistance of fabricated gas detectors has been observed at DC bias of 5 V and low operating temperature 250 degrees C. Specifically, when concentration of H2S gas increases from 0-10 ppm, average resistance of the S-425 and S-450 gas sensors was observed to decrease by 96.5% and 97.6%, respectively. In general, the sensing mechanism of gas sensors proposed in this work can be associated with ionosorption of oxygen species over WO3 nanostructured surfaces. However, the significantly enhanced sensing performance of S-450 sensor may be attributed to improved crystallinity in its structure and improved ions adsorption/desorption kinetics at nanorods surface morphology.