Identification of the reaction mechanism of the Pt, O2(g)|yttria-stabilized zirconia system -: Part II:: Model implementation, parameter estimation, and validation

In order to find the kinetic parameters of porous Pt, O-2(g)\yttria-stabilized zirconia electrodes, electrochemical impedance spectra were obtained at T=1071 K and 975 K in the p(O2) range of (1...10(-4)) atm. A numerical optimization technique was employed to estimate the unknown kinetic parameters of the reaction model examined in part I of the present paper. The exchange coefficient beta, the rate constants for the electron transfer k(1), for oxygen adsorption k(a), for oxygen desorption k(d), and the Fickian surface diffusion coefficient D(theta) of atomic oxygen on polycrystalline Pt were estimated at T=975 K and p(O2)=1 atm. The results were validated in terms of the proposed model. (C) 1999 Elsevier Science B.V. All rights reserved.