ChemInform Abstract: Electrocatalysis and Inductive Effects at the Gas, Pt/Stabilized Zirconia Interface.

ChemInform Abstract

It is shown that electrocatalyzed reactions at the gas, Pt/yttria-stabilized zirconia (YSZ) electrode can occur at both the anode (O2 evolution reaction) and the cathode (H₂O vapor reduction). Both reactions are promoted by the onset of electronic conductivity at the surface of the solid electrolyte, which results from an increase in the electron hole concentration in the electrolyte subsurface occurring under appropriate experimental conditions. Transition from pure ionic to mixed ionic and electronic subsurface conductivity is reflected by a sharp decrease in the corresponding overvoltage and by a drastic modification of the impedance spectra. The promoting effect of electronic defects is clearly demonstrated. The spreading of the electrode reaction zone around the triple contact point,also caused by the mobile electronic defects, also contributes as a "geometrical" effect to the increase in the reaction rate.