Sulfur Gas Sensor Using a Calcium Fluoride Solid Electrolyte

Abstract

The sulfur gas potentials in the H2S+H2 buffer gases were measured by a galvanic cellPs2)(normalg,normalAu)(normalPt|)(MoS2+normalCaS|CaF2|)(normalCu+Cu2S+normalCaS|normalAu)(normalPtin the temperature range from 650° to 950°C and Ps2 region from 10−2 to 10−10 atm. A quick response time (within 5 to 10 min) in emf with the change of Ps2 at a given temperature was observed by placing a MoS2 and normalCaS mixed pellet auxiliary electrode at the bottom of the cylindrical single‐crystal CaF2 electrolyte. The observed emf's agreed well with those calculated from the Nernst equation. Using this sensor, Ps2 values in the SO2+H2+H2S gas system were also evaluated from the measured emf at 827°C and were found to be in close agreement with those calculated from the thermochemical tables.

A highly selective chemiluminescent H2S sensor

“…As we described before, solid electrolyte sensors based on CaS show a long response time about 10 4 s [5]. The semiconductor H 2 S sensors often show a response time about several minutes [6,7].…”

“…The following is the abbreviation of the chemicals and the corresponding manufacturers: (NH 4 ) 5 [13]. Ferric hydroxide was precipitated from an aqueous solution of FeCl 3 with ammonia, washing with water, and calcinations in air at 600 • C for 3 h. CaO, Al 2 O 3 and ZrO 2 were prepared by the same method.…”

“…Most of methods for determination of H 2 S are based on the use of electroanalytical techniques [2][3][4][5][6][7][8][9]. For example, various electrochemical H 2 S sensors based on direct apmperometric [2], voltammetric [3], or cathodic stripping [4] measurements in liquid electrolytes have been suggested.…”

“…The solid state sensors avoid the problems from using liquid electrolytes, therefore they can be stable, compact and portable. Solid electrolyte sensors [5] have been studied, however, their disadvantages are the slow response (10 4 s to equilibrium) and high working temperature (1200 K). Much effort has been made to develop semiconductor metal oxide H 2 S sensors [6][7][8][9].…”

Measurement of the standard molar Gibbs free energy of formation of Ag2S using Ag+β-alumina solid electrolyte

“…sulphur activity changes) was excellent and appeared to be accelerated by the presence of molybdenum sulphide. Taniguchi et al (5) and also obtained a steady e.m.f. within 10 min.…”