Electrochemical processes of H2S detection in air and solution

An electrochemical cell of potentiometric type Na0.5WO3 (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 +/- 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.