Design, fabrication, and characterization of low-power gas sensors based on organic-inorganic nano-composite

Abstract

Low-power and selective H2S gas sensors based on tungsten oxide (WO3) nanoparticles (NPs) embedded in organic polymer membranes are presented in this study. WO3 NPs were synthesized using the sol-gel method. Polymer solutions consisting of poly-vinyl-alcohol (PVA) and ionic liquid (IL) were doped with WO3 NPs. Then, the doped solutions were casted to obtain flexible membranes (200 μm in thickness). The sensors (PVA-IL-WO3 NPs membranes) were tested to investigate their gas sensing performance by measuring the electrical current response signals at different operating temperatures. The result revealed that the best response to H2S gas for all sensors was obtained at 80 °C, yet a reasonable response was noticed at a low operating temperature of 20 °C. As a result, the power consumed to heat up the sensor is reduced by almost 89%. The detection limit of the sensor was 10 ppm and the results showed a fast response of 19.1 ± 3.4 s. Moreover, these sensors exhibited excellent reproducibility and stability, and were identified to be selective to H2S. In addition to the aforementioned qualities, the sensors were characterized by their ease of fabrication, flexibility, and their low cost. Due to all these characteristics, these sensors were identified to be promising materials for hazardous H2S gas sensing applications.