Abstract
The potential-step chronoamperometry method has been applied to Pt/yttria-stabilized zirconia and Pt/samaria-doped ceria air cathodes, and current decay curves in response to applied potentials have been measured. It was assumed that oxygen ad-atoms formed by dissociative adsorption on platinum surface diffuse through the platinum electrode-solid electrolyte interface and then are reduced electrochemically to oxide ions. A decay equation was derived on the basis of the above reaction model. The kinetic parameters involved in it were determined by curve-fitting to the experimental values. The exchange current density and interfacial diffusivity were calculated from the parameter values thus obtained.
