Sulfur dioxide gas sensor based on Zr4+ and O2− ion conducting solid electrolytes with lanthanum oxysulfate as an auxiliary sensing electrode

A solid electrolyte type SO2 gas sensor based on tetravalent Zr4+ ion conducting Zr39/40TaP2.9W0.1O12 and O2− ion conducting (ZrO2)0.92(Y2O3)0.08 solid electrolytes with 0.7La2O2SO4–0.3(0.8Li2SO4 + 0.2K2SO4) as an auxiliary sensing electrode was developed. The present sensor exhibited a continuous, reproducible, and quantitative response for SO2 gas, and the relationship between the sensor EMF output and the logarithm of the SO2 gas concentration obeyed the Nernst equation at temperatures as low as 480 °C over 80 days. Thus, it is expected to be a good candidate as a practical SO2 gas sensor for on site measurements.