An electrochemical sulfur sensor based on ZrO 2(MgO) as solid electrolyte and ZrS 2 + MgS as auxiliary electrode

Abstract

A sulfur sensor Mo|Mo, Mo 2S 3|ZrS 2 + MgS|ZrO 2(MgO)|ZrS 2 + MgS|[S] Fe|Mo was developed and tested in carbon-saturated liquid iron. The auxiliary electrode was ZrS 2 + MgS, which was formed on the surface of ZrO 2(MgO) electrolyte by: ZrO 2(MgO)(s) + 3H 2S(g) = ZrS 2(s) + MgS(s) + 3H 2O(g). The results indicate that the auxiliary electrode is dense, and has a good adhesion to the solid electrolyte. ZrS 2 and MgS are stable in the carbon-saturated liquid iron where the a O < 1.25 × 10 −7 at 1550 K and a O < 2.10 × 10 −7 at 1600 K. The variations of the EMF versus [wt% S] can be obtained as follows: E = − 65.48 ln [ wt % S ] + 134.42 ( 1550 K ) E = − 81.18 ln [ wt % S ] + 111.66 ( 1600 K )