SO2ガスセンサの開発に関する基礎的研究
1984 年 100 巻 1157 号 p. 603-607
詳細
1984 年 100 巻 1157 号 p. 603-607
In the present study, the following three kinds of concentration cell were constructed and equilibrium e.m.f. were measured in the temperature range of 873-1173 K (Cell I, II) or 873-1373 K (Cell III).
Pt, SO2, SO3, O2/Na2SO4/SO2'SO3', O2', Pt.cell I
Pt, SO2, SO3, O2/Na2SO4/β-Al2O3/Na2SO4/SO2', SO3', O2', Pt.cell II
Pt, SO2, SO3, O2</β-Al2O3, /SO2', SO3', O2', Pt.cell III
In every cell, the left hand electrode, that is the reference electrode, was composed of 9020 or 9470 ppm SO2 and balanced by air and right hand electrode, that is sample electrode, was composed of air containing many kinds of SO2 content.
From the experimental results the following facts were confirmed.
Provided that the Na2SO4 solid electrolyte pellet was made under the enough pressure, the stable and reliable e. m. f. values were measured and those found to be in agreement with the theoretical values calculated based on the thermodynamic values under the condition even if the ratio of PS02 (sample)/PS02 (reference) is 1/100.
However the construction of tube consisted of Na2SO4 is very difficult and we tried the use of β-Al203 tube replaced with Na2SO4 pellet as a solid electrolyte. In the experiment by using cell II, 5-10 mV higher values than the theoretical were measured and those values were stable and good reproducibility. Furthermore the response to the change of SO2 content in air was as good as cell I. In the experiment by using cell III, the stable and good reproducible e.m.f. values were measured and those were in good agreement with the theoretical values.
ere in good agreement with the theoretical values. The response to the change of SO2 content was a little worse than cell-I or II. However it could be concluded that the β-Al2O3 was proposed the very appropriate solid electrolyte for commercial SO2 sensor which will be developed in near future.
