SOLID-STATE BR-2 SENSOR OPERATING AT ROOM-TEMPERATURE

A galvanic-cell type Br, sensor working at room temperature has been s uccessfully made by using a RuO2 sensing electrode, a PbBr2-KBr solid electrolyte and a Pb reference electrode. The sensor cell arrangement can be represented as Pb\PbBr2 + 3 mol% KBr\Br-2, RuO2. The open circu it EMFs of the cell measured at room temperature were reproducible and agreed closely with the values calculated from Nernst's equation in t he concentration range of 0.00075 vol% to 25.7 vol% of Br-2 in air. Th e 90% response times of the sensor for step changes of the Br-2 concen tration were less than I min at concentrations higher than 0.1 vol%.