Temperature programmed isotopic exchange of lattice oxygen during methane oxidative coupling

Abstract

Temperature programmed isotopic exchange (TPIE), has been applied in the studies of the oxidative coupling of methane. Results presented in this paper show that the addition of strontium oxide to lanthanum oxide changes a structure of La2O3 by creating oxygen vacancies in its lattice. TPIE experiments indicate that an exchange between gas phase and lattice oxygen for the 1% Sr/La2O3 starts below 400 ° C and a starting exchange temperature (SET), is around 100 ° C lower than in the case of unpromoted La2O3. In this paper the effect of other operating variables (oxygen partial pressure, presence of methane, and carbon dioxide), on the isotopic exchange rates for lanthanum oxide based catalysts is also demonstrated.