Development and testing of HCl gas sensor for flue gas monitoring

A novel solid-state sensor for monitoring HCl gas incorporating a unique combination of two solid electrolytes, strontium cerate (SrCeO3) doped with 10 mol% neodymium oxide (Nd2O3) that can exhibit protonic conduction at temperature greater than or equal to 773 K, and strontium chloride (SrCl2) which is a chloride ion conductor, has been developed. The optimum composition for the doped cerate has been found to be (0.7)SrO.CeO2 containing 10 mol% Nd2O3, produced by calcining the raw materials at 1573 K and sintering the fabricated tube at 1773 K. Sensors gave reproducible electromotive force (e.m.f.) with varying partial pressure HCl gas in argon at temperatures above 773 K.