High temperature water electrolysis: the cathodic process at the Cermet (Pt+La0.8+Sr0.2CrO3)/Zirconia interface

The kinetics of the reduction of steam at the interface of a platinum containing cermet with Yttria Stabilized Zirconia (YSZ) electrolyte at high temperature has been investigated. The presence of an outer porous platinum layer deposited onto the underlying cermet layer results in a remarkable increase of the kinetic parameters of the overall reaction. However, the presence of metallic platinum embedded in the structure of the mixed oxide layer, restricting the section available for the diffusion of the reducible species, results in a worsening of the electrochemical kinetics. A comparison with other previously investigated electrodes has been performed and some hypotheses on the rate determining mechanism have been suggested. © 1988.