(BaxLa1-x)(2)In2O5+x (0.4 = x = 0.6) electrolyte-supported mixed-potential CO sensors

摘要

The dense (BaxLa1-x)(2)In2O5+x electrolytes with different compositions (x = 0.4, 0.5, 0.6) were synthesized by Pechini method. The obtained sintered (BaxLa1-x)(2)In2O5+x electrolytes showed a high relative density of similar to 98%, and the major phase of three electrolyte compositions was indexed as a cubic phase. The CO sensing properties of as-fabricated planar-type (BaxLa1-x)(2)In2O5+x-based sensors coupled with ITO and Pt as the sensing electrode and reference electrode, respectively, were investigated. The effects of factors such as gas flow rate, chemical compositions, and density of the electrolytes on the sensing performance were investigated. The sensors showed good sensitivity to different concentrations of CO from similar to 100 to similar to 500 ppm and excellent selectivity over low concentrations of methane (< 50,0 ppm). Linear relationships between emf of the sensors and CO gas concentrations from similar to 100 to similar to 400 ppm were observed. However, the sensors indicated more sluggish response compared with the sensors coupled with a corresponding porous electrolyte. The probable reason has been discussed. The long-term stability of the sensor for the detection of CO was also investigated, which indicated a reasonably stable sensor signal after an initial decline during the incubation period.