Work function changes and electrochemical pumping of platinum electrodes on yttrium stabilized zirconia

The work function (WF) changes which are induced by electrochemical pumping on porous Pt electrodes on yttrium stabilized zirconia (YSZ) have been studied with a Kelvin probe as an integral and a photoemission electron microscope as a spatially resolving method, respectively. The comparison of the measurements demonstrates that besides true spillover via surface diffusion of oxygen, electrostatic effects are also present. These electrostatic effects arising from the fact that not all parts of a porous metal electrode are in electrical contact contribute to the WF signal measured with a Kelvin probe. Experiments with Pt electrodes prepared differently show that the preparation of the porous metal electrodes has a strong influence on the electrostatic contribution.