Study On Fuel Cell Gas Sensor Used For Atmospheric Environmental Monitoring

Up to now, the study of fuel cell mostly focus on energy sources, i.e. the application for mass generating electricity, various disperse and locomotive power supplies. However, few study has been undertaken concerning fuel cell used for atmospheric environmental monitoring.Based on fuel cell technology and gas sensor, this paper investigated the feasibility of fuel cell used for atmospheric environmental monitoring. The work which has been developed primarily involved(1)preparation of porous gas diffusion electrodes, (2)compare and selection of different porous gas diffusion electrodes, (3)selection of different electrolyte solutions, (4)assembly of fuel cell with selected porous gas diffusion electrodes and electrolyte, and testing the response for reductive gases SO2 and H2S under the experimental conditions.The result showed good linear range between response current and the concentration of SO2 over the range from 67ppm to 668ppm(linear regress equation is Y=0.5901X-32.4,R2=0.9993)with aqueous 10%H2SO4 electrolyte, associated with special electrode Eai as anode and special electrode Eci as cathode in the fuel cell. The response time(to.9) is about 30s,the sensitivity is 0.59uA ppm-1, the detection limit is 55ppm.Under normal temperature, for the concentration of 134ppm and 668ppm SO2,the RSDs(n=6) are 7.3% and 1.2% respectively. When the fuel cell was filled with aqueous 10%H2SO4 electrolyte containing 0.1%Mn2+,associated with special hydrogen electrode Eh3 as anode and Pt air electrode EG3 as cathode, the fuelcell response current showed good linear range to H2S over the range from 200ppm to 1000ppm(linear regress equation is Y=0.1567X-25.449,R2=0.9956).The response time(to.9)is about 3s,the sensitivity is 0.1GuAppm-1,the detection limit to H2S is 162ppm. Under normal temperature, for 200ppm and 800ppm H2S,the RSDs(n=6) are 7.9% and 5.2% respectively.The primary work proved that the fuel cell gas sensor based on gas diffusion electrodes showed good linear response to SO2 and H2S.lt would be feasible to apply to atmospheric environmental monitoring, if gas diffusion electrodes were optimized and the structure of fuel cell was improved.Applying the fuel cell to atmospheric environmental monitoring, it would possess the advantages of providing fast, simple, handy, exact and 'in situ' detection to gaseous analyte. Moreover, without need power supply, it is miniature, portable and apt to realize on-line, continuous, automatic monitoring. Based on this study, it will be expected to set up a new method used for atmospheric environmental monitoring.