Surface Reaction Kinetics of Oxygen on La1−xSrxCoO3−δ Cathode

Oxygen reaction kinetics was investigated with a dense film of (La,Sr)CoO 3−δ on ceria based electrolytes. The rate determining step for a highly Sr doped sample was confirmed to be the surface reaction that included at least two series processes, i.e. oxygen adsorption from the gas phase and oxygen transfer across the sub surface layer of the electrode. The reaction rates of those processes were determined separately by using a porous oxygen sensor (POS) which measures the surface oxygen potential on the working electrode. Empirical equations and the kinetic parameters were obtained. The sub surface oxygen transfer process had higher activation energy, and became important in lower temperature applications.