TRANSIENT STUDIES ON OXYGEN ACTIVATION ON A SM2O3 SURFACE IN THE OXIDATIVE COUPLING OF METHANE

The interaction of N2O with a Sm2O3 surface and the reaction of methan e with surface oxygen species from N2O decomposition were studied appl ying the temporal-analysis-of-product (TAP) reactor. Formation of C-2 hydrocarbons depended on the concentration of adsorbed oxygen buut the overall reaction was limited by the rate of N2O decomposition which w as lower than that of the dissociative adsorption of molecular oxygen under the conditions applied. It might be assumed that the fast transf ormation of O or O- initially produced by dissociative adsorption of N 2O resulted in the formation of adsorbed oxygen species similar to tho se formed by interaction of gas-phase oxygen with the samaria surface at low temperature (908 K). Different surface processes are suggested to be responsible for the activation of these two oxidants.