Formulation and catalytic performance of MOF-derived Fe@C/Al composites for high temperature Fischer–Tropsch synthesis

Abstract

High productivity towards C₂–C₄ olefins together with high catalyst stability are key for optimum operation in high temperature Fischer–Tropsch synthesis (HT-FTS). Here, we report the fabrication of Fe@C/Al composites that combine both the outstanding catalytic properties of the Fe–BTC MOF-derived Fe catalyst and the excellent mechanical resistance and textural properties provided by the inorganic AlOOH binder. The addition of AlOOH to Fe–BTC followed by pyrolysis in N₂ atmosphere at 500 °C results in composites with a large mesoporosity, a high Fe/Fe₃O₄ ratio, 10–35 nm average Fe crystallite size and coordinatively unsaturated Al³⁺ sites. In catalytic terms, the addition of AlOOH binder gives rise to enhanced C₂–C₄ selectivity and catalyst mechanical stability in HT-FTS, but at high Al contents the activity decreases. Altogether, the productivity of these Fe@C/Al composites is well above most known Fe catalysts for this process.