Kinetics of interaction of gas phase oxygen with cerium-gadolinium oxide

The method of isotopic exchange with gas phase analysis was used to study the kinetics of oxygen interaction with the Ce_0.80Gd_0.20O_{1.90 ? ??} oxide at the oxygen pressure of 0.27?C1.33 kPa in the temperature range of 700?C800°C. The values of oxygen interphase exchange rate and diffusion coefficient, and also effective activation energies of the processes of oxygen exchange and diffusion were determined. The contributions of three exchange types and amounts of equivalent exchangeable oxygen were calculated. It was shown that the limiting exchange stage is the process of dissociative oxygen adsorption/desorption on the surface of the Ce_0.80Gd_0.20O_{1.90 - ??} oxide.