High thermal conductive core-shell structured Al2O3@Al composite supported cobalt catalyst for Fischer-Tropsch synthesis.

High thermal conductive Al 2 O 3 @Al composite synthesized via metallic Al powders corrosion method has been applied as support for preparing Co/Al 2 O 3 @Al catalyst for high exothermic Fischer-Tropsch synthesis. The prepared Al 2 O 3 @Al composite is a hierarchical macro-mesoporous structure and consist of two parts, namely the inner metallic Al and the outer Al 2 O 3 with two kinds of morphologies. Increasing the concentration of the corrosive NaOH or extending the corrosion time could increase the specific surface area of the composite. For the prepared Co/Al 2 O 3 @Al, Co 3 O 4 phase is located on the outer plate-like Al 2 O 3 layer. The Co/Al-0.03-20 possesses higher CO conversion and C 5+ selectivity due to the appropriate cobalt reducibility, dispersion and high thermal conductivity. The thermal conductive coefficient of Co/Al 2 O 3 @Al catalysts is 13–98 times of conventional Co/Al 2 O 3 . Compared to Co/Al 2 O 3 , the Co/Al 2 O 3 @Al shows higher CO conversion and C 5+ selectivity as well as lower CH 4 and CO 2 selectivity, which is attributed to the macro-mesoporous structure and high thermal conductivity. In addition, because of the high thermal conductivity, no heat disperser should be used and a homogeneous temperature gradient maintains within the catalyst bed for Co/Al 2 O 3 @Al. [ABSTRACT FROM AUTHOR]