Oxygen Transfer on Substituted ZrO2, Bi2 O 3, and CeO2 Electrolytes with Platinum Electrodes: I . Electrode Resistance by D‐C Polarization

The electrode behavior of Pt‐sputtered and PT‐gauze electrodes on ZrO 2 ‐ Y 2 O 3 , Bi 2 O 3 ‐ Er 2 O 3 , and CeO 2 ‐ Gd 2 O 3 solid electrolytes was investigated by means of d‐c measurements in the temperature region of 770–1050 K and in the oxygen partial pressure region of 10 − 5 – 1 atm O 2 using N 2 ‐ O 2 mixtures. On these different materials the same electrode morphology was realized and was preserved during the subsequent experiments. The electrode process is strongly influenced by the nature of the electrolyte. The electrode resistance for Pt electrodes on Bi 2 O 3 ‐ Er 2 O 3 was found to be many times lower than on ZrO 2 ‐ Y 2 O 3 and CeO 2 ‐ Gd 2 O 3 . On zirconia‐ and ceria‐based materials diffusion of atomic oxygen on the Pt electrode is the rate‐determining step in the electrode process, whereas for bismuth sesquioxide‐based materials diffusion on the oxide surfaces is rate determining.