Polarization conductivity of the Pt,O2/La0.88Sr0.12Ga0.82Mg0.18O2.85 electrode system:: Dependence on the partial oxygen pressure and temperature

In this work, dependences of the polarization conductivity in the vicinity of an equilibrium potential for the Pt. O-2/La0.88Sr0.12Ga0.82M0.18O2.85 electrode system on the partial pressure of oxygen in a gas environment and the temperature in the region 3-10(5) C Pa and 816-1147 K, respectively, are obtained. A model of two parallel routes for the occurrence of an oxygen reaction is proposed. It is presumed that one route is localized at the platinum/gas interface and is limited by the process of surface diffusion of adsorbed oxygen over the platinum surface to the triple-phase boundary electrode/electrolyte/,-as. The other route of the reaction consists of that the electronic holes that are generated at the electrolyte/gas interface diffuse towards the electrolyte/electrode interface and recombine with the electrons of platinum on the latter. The limiting stage of the second route is the transport of holes in the electrolyte. Calculations, which were performed in accordance with the model described, led to a good description of experimental data. Comparing calculated values of the enthalpy for the oxygen adsorption on platinum, the activation energy for the oxygen diffusion over the platinum surface, and the activation energy for the transport of holes in the electrolyte with the literature data shows good correspondence between them. which speaks of adequacy of modeling concepts to real processes in the electrode system studied.