Electrochemical processes of H₂S detection in air and solution

Abstract.

An electrochemical cell of potentiometric type Na_0.5WO₃ (reference electrode)/Na⁺-solid electrolyte/PbS (working electrode) capable of rapid and selective changing of the electromotive force value owing to H₂S concentration variations in gas surroundings has been investigated at 295±1 K and a relative humidity of 52%. The sensitivity of this cell was 130 mV/decade at a H₂S concentration within the range 13–130 ppm. Sodium-conducting solid electrolytes of Na₃Zr₂Si₂PO₁₂ and Na₅GdSi₄O₁₂ compositions were used as the Na⁺ solid electrolyte. Such a cell can be used for analysis of H₂S containing water solutions when the reference electrode and the Na⁺ solid electrolyte are thoroughly isolated from the surroundings.