ELECTROMOTIVE-FORCE RESPONSES OF CL2 GAS SENSOR USING BACL2-KCL SOLID-ELECTROLYTE

A Cl2 gas sensor using BaCl2-KCl solid electrolyte was investigated. The conductivity was greatly enhanced by KCl doping of the (1 - x) BaCl2-xKCl system, and a maximum conductivity of 5.6 x 10(-5) S . cm-1 at 573 K was obtained for x = 0.02. The sensor probe was prepared by a melting method at 1373 K. The electromotive force (EMF) measurement with the Cl2 gas sensor using the 0.97BaCl2-0.03KCl solid electrolyte was performed with an Ag-AgCl solid reference electrode and an RUO2 measuring electrode. Good agreement between the measured and the calculated EMF values was obtained for Cl2 gas concentrations from 50 to 10,000 ppm at 623 K. The EMF response time with a change in Cl2 concentration is ca. 1 min for above 100 ppm and 2 to 5 min for lower concentrations. The measured EMF was not influenced by O2 or CO2 gas concentration. This sensor probe was very stable in the presence of water vapor at 623 K during a 90 day test period.