Deactivation of bulk iron oxide catalysts during methane combustion

摘要

The deactivation of bulk iron oxide during methane combustion has been studied. The observed deactivation behaviour has been explained as the result of two simultaneous deactivation mechanisms. In the initial phase of reaction both are in operation and the activity drops rapidly as a consequence of both catalyst sintering and of the depletion of lattice oxygen in the outer layers, due to a partial reduction of the catalytic surface. In later stages, catalyst deactivation is almost exclusively due to sintering under reaction conditions. A kinetic model of deactivation is presented, together with the physiochemical characterization of fresh and partially deactivated catalysts.