H2S sensors based on tungsten oxide nanostructures

Nanoparticles and nanoplatelets of WO3 and nanowires of WO2.72 have been investigated for their H2S-sensing characteristics over the 1–1000 ppm concentration range at 40–250 °C. The nanoparticles and nanoplatelets of WO3 exhibit response values of 757 and 1852, respectively to 1000 ppm H2S at 250 °C, respectively, compared to the response of 3313 of the nanowires of WO2.72. Interestingly, the response of the nanowires is satisfactory (121) to 10 ppm H2S at 250 °C, while a large response (240) is observed to 1000 ppm H2S even at 40 °C. The WO2.72 nanowires emerge as a good candidate for H2S sensors, with little effect of humidity up to 60% relative humidity as well as satisfactory response and recovery times.