RATE ANALYSIS BY POTENTIAL-STEP CHRONOAMP EROMETRY IN PT YSZ AIR CATHODES/

This study aims to separate the polarization resistance of Pt/YSZ air electrodes into two resistance components, i.e., dissociative adsorpti on resistance and diffusion resistance. Current decay curves were meas ured by potential-step chronoamperometry and a current decay equation was obtained by solving Fick's diffusion equation under appropriate bo undary conditions. The experimental decay curves were fitted to the eq uation by optimizing parameter values involved in the equation. Diffus ion coefficients and rate constants for adsorption were calculated fro m the parameter values thus obtained. It was found that the rate contr olling step depends on temperature, oxygen pressure and sintering temp erature of electrodes.