Gas sensing unit

摘要

Methods and apparatus are provided for sensing reducible gases in the environment. The invention herein utilizes electrochemical sensing procedures incorporating gold as the sensing electrode in combination with a material selected from the group of iridium and ruthenium as the counterelectrode. This combination avoids the usual polarization at the anode in prior arrangements of this kind and the gradual degradation in the degree of sensing specificity for sensing, for example, NO2 and Cl2. In those instances wherein a three electrode system is used, the third or reference electrode may be comprised of platinum, iridium or ruthenium.