OP-II-3

PP-I-4412R surfR surf0 2 4 6 8R surfbulkD slowD slow R bulkR surf18 OFast diffusionthrough vacanciesor interphaseboundaries-2·s-1W, 10 -5 mole·m1086420D, 10 -14 -1m2·sFig. 1. Scheme of gas / surface(subsurface) /bulk oxygenexchange in themixed oxides.Fig. 2. The specific catalytic activity with regard toCH 4 combustion (□) or N 2 O decomposition (■) versuscoefficient of oxygen diffusion dependence forLa-Sr-Mn-O mixed oxides. T = 900°C.All intrinsic kinetic parameters related to oxygen activation and diffusion both inthe mixed oxides and in the metal – mixed oxide systems were calculated by thenumerical analysis of experimental curves in accordance with proposed models.The obvious correlation between the coefficient of oxygen diffusion in perovskiteor fluorite based catalysts and their specific activity in a large number of reactionswith participation of oxygen was found. Fig.2 shows the examples of such correlationfor the catalytic systems “perovskite - methane oxidation” and “perovskite – N 2 Odecomposition”.Performed study shows a decisive role of lattice oxygen mobility in the hightemperature catalytic activity of mixed oxides in the reaction with oxygenparticipation.300