An All-Solid-State Potentiometric SO_2 Gas Sensor with Solid Reference Electrode

摘要

A SO_2 sensor based on Na-p-Al_2O_3 interfaced with an auxiliary electrode of Na_2SO_4 formed in-situ and a solid mixture of Fe_3O_4,Fe_2O_3,3Na_2O(centre dot)5Fe_2O_3 as the reference electrode was developed.The sensor displayed a good response to changes in the partial pressure of SO_2 with a linear relationship between the measured emf and the logarithmic values of the partial pressure of SO_2,as predicted by the Nernstian equation.Using an electron probe X-ray microanalyser,the formation of a Na_2SO_4 reaction layer was confirmed on the surface of Na-p-Al_2O_3 tube due to surface reaction with the SO_2 gas.