Amperometric gas sensors based on screen printed electrodes with porous ceramic substrates

摘要

In the present study, an amperometric gas sensor based on room temperature ionic liquid (RTIL) electrolyte and screen-printed electrodes (SPE) was fabricated. In order to compose the sensor device, a porous alumina ceramic was used as gas diffusion barrier and substrate of SPE, simultaneously. While RTIL electrolytes were also solidified with casting method to form a solid film and attached onto porous ceramics equipped with printed electrodes. It was found that with this design, the amperometric sensor could become smaller and easier to intergrade. Additionally, the porous ceramics as the diffusion barrier as substrate enable gas molecules diffuse into the three-phase (gas/electrode/electrolyte) interface directly without passing through RTIL membranes. For demonstration, an amperometric nitrogen dioxide (NO_2) sensor was composed with our proposed structure and the sensing performance were characterized in terms of sensitivity, selectivity and stability. It was indicated that indeed our NO_2 sensor show a very rapid response speed, only 20 s and 10 s for responding and recovering, respectively. This is 4 times shorter than the traditional sensor structure based on RTIL. In addition, the sensor has a good sensitivity (33 nA / ppm) and limit of detection (LOD) around 0.02 ppm with a signal noise ratio (SNR) around 3. It was also detected that the sensor has a wide operating temperature range (-20 to 40 °C), suggesting our sensor devices could work in extreme environments.