In this work, sodium dodecyl benzene sulfonate (SDBS) was used as a dispersing agent; a WO3 nanoparticle suspension was used as a sensing material. The SDBS-WO3 thin film/Sn-doped glass optical waveguide sensor element was prepared by spin coating. The sensing material was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM). The gas-sensing characteristics of the fabricated sensors were studied at room temperature for various gases. The experimental results indicate that the sensor exhibited a high selective response toward SO2 and H2S and a low detection limit of 10 ppb to SO2 and H2S. The response/recovery times for SO2 and H2S were 2/23 and 2/18 s. However, during an electrochemical gas-sensing performance test of the SDBS-WO3 film at room temperature, the results indicated that the trend of the variation in resistance was consistent with the variation in the output light.
Keywords: H2S; SO2; WO3; electrochemical gas sensor; optical waveguide gas sensor.