Effect of Confinement in Carbon Nanotubes on the Activity of Fischer−Tropsch Iron Catalyst

Following our previous findings that confinement within carbon nanotubes (CNTs) can modify the redox properties of encapsulated iron oxides, we demonstrate here how this can affect the catalytic reactivity of iron catalysts in Fischer-Tropsch synthesis (FTS). The investigation, using in situ XRD under conditions close to the reaction conditions, reveals that the distribution of iron carbide and oxide phases is modulated in the CNT-confined system. The iron species encapsulated inside CNTs prefer to exist in a more reduced state, tending to form more iron carbides under the reaction conditions, which have been recognized to be essential to obtain high FTS activity. The relative ratio of the integral XRD peaks…