Research on Thin Film type Hydrogen Sulfide Sensor Based on SnO2-CuO Nanofibers / 分析化学

ABSTRACT

A SnO2-CuO composite nanofiber was prepared by the coaxial electrospinning method. A new thin-film-type hydrogen sulfide gas sensor was designed by coating SnO2-CuO composite nanofibers onto an alumina ceramic tube with Au electrodes by dip-coating method. The crystalline phase and microstructure of SnO2-CuO composite nanofibers were characterized using X-ray diffraction ( XRD ) and scanning electron microscope ( SEM) . The influence of chemical composition and thickness of sensitive film on the sensitive mechanism and electrochemical characteristic of SnO2-CuO nanofibers were analyzed. The characteristic tests of hydrogen sulfide sensor including sensitive performance, temperature, relative humidity, dynamic response, interference and stability were carried out by WS-30A type multifunction analyzer in gas sensor test system. The results demonstrated that, when the operating temperature was 25℃ and hydrogen sulfide gas concentration increased from 10 to 60 mg/L, the hydrogen sulfide sensor based on C50 composite nanofibers with 70 nm sensitive film thickness had the best linearity (92. 3%) and sensitivity (98. 2%). Besides, its highest response values and relatively humidity level were 1080 and 95%, respectively, and its dynamic response time and recover time were 4 s and 12 s, respectively. This sensor showed good anti-disturbance to the gases, such as CO, NO2 , SO2 , NH3 , CO2 , CH4 and H2 . The response value of the sensor was attenuated about 9. 2% when it was applied continually in the mine about 12 months, and its normal response time was 10. 9 months.