ELECTRODE-POTENTIALS IN THE SYSTEM SOLID FLUORINE-CONDUCTING ELECTROLYTE-NICKEL OXYFLUORIDE-PLATINUM-CARBON MONOXIDE

Behavior of electrochemical cells with a solid fluorine-conductin,o el ectrolyte based on PbF2 is investigated in a gaseous environment compo sed of air and CO (the CO concentration in the interval 10(-5) to 10 v ol %) at room temperature. Variations in the emf of the sensing electr ode based on nickel oxyfluoride is connected with changes in the conce ntration of electrons and holes. A theoretical model is proposed for o xide ionic-electronic semiconductor electrodes that describes the depe ndence of emf on the concentration of CO and H-2. The emf vs. log CO d ependence in the region of p-type conduction of nickel oxyfluoride is nonlinear, whereas in the region of n-type conduction, this dependence is linear and has a slope close to the calculated value 55 - 60 mV. I n the region corresponding to the transition from p-type conduction to n-type conduction, emf is observed to sharply change, and the magnitu de of the jump depends on the ratio between the concentration of ioniz ed acceptors of the initial oxyfluoride and the concentration of elect rons of stoichiometric nickel oxyfluoride.