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

A Cl2 gas sensor using BaCl2-KCl solid electrolyte was investigated. T he conductivity was greatly enhanced by KCl doping of the (1 - x) BaCl 2-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 me lting 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 measur ing electrode. Good agreement between the measured and the calculated EMF values was obtained for Cl2 gas concentrations from 50 to 10,000 p pm 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 62 3 K during a 90 day test period.