HIGH-PERFORMANCE SOLID-ELECTROLYTE SOX SENSOR USING MGO-STABILIZED ZIRCONIA TUBE AND LI2SO4-CASO4-SIO2 AUXILIARY PHASE

Solid-electrolyte-based electrochemical SOx sensors fabricated with Mg O-stabilized zirconia and Li2SO4-CaSO4SiO2 (4:4:2 in molar ratio) exhi bit fairly good sensing characteristics for 2-200 ppm SO2 in air at 60 0-750 degrees C, with their e.m.f. responses following the Nernst equa tion for the two-electron reduction of SO2. The 90% response and 90% r ecovery times to 20 ppm SO2, are 10 s and 7 min at 650 degrees C, and 10 s and 3 min at 700 degrees C, respectively. It is further found tha t the sensor exhibits excellent selectivity to SOx in the coexistence of CO2 and NOx, and good long-term stability. The sensor is simple in structure, easy to prepare, and quite tough chemically and mechanicall y. These features should ensure practical use for this SOx sensor.