FAST RESPONSE OF AMPEROMETRIC OXYGEN SENSORS BASED ON AN IRON PHTHALOCYANINE-BASED SENSING ELECTRODE AT AMBIENT-TEMPERATURE

To improve the slow response of ambient temperature fluoride-based oxygen sensors, we propose an amperometric one of the type Ag/Ag6I4WO4/PbSnF4/sensing electrode (SE), O2 based on the fast ion conductors, Ag6I4WO4 and PbSnF4, and an iron phthalocyanine(FePc)-based SE mixture of FePc, platinum-black, and PbSnF4. Oxygen partial pressures (P(O2)) in the range 2-300 kPa can be determined under either reduced or elevated pressure by measuring the short-circuit current since this increases linearly with P(O2)1/2. The 90% response time (t90) depends strongly on FePc content. The shortest t90, 30-45 s, is comparable to that of galvanic cell-type sensors.