New shearing mechanical coating technology for synthesis of alumina-supported cobalt Fischer–Tropsch solid catalysts

Abstract

This study presents a novel dry coating technology for Co/Al₂O₃ catalyst synthesis without solvents and heating treatment. Nano crystallized Co₃O₄ powders were mechanically coated onto γ-Al₂O₃ using an advanced high-shear batch mixer “Picomix”. The interaction between support and Co₃O₄ was produced by the shearing force of the blades in the jar and the van der Waal adhesion force. A uniform coating layer of a 1 μm to 3 μm thickness was observed. The diffusion of Co₃O₄ into γ-Al₂O₃ pores did not occur, resulting in the formation of an “egg-shell” structure. Undesirable cobalt aluminate compounds that are difficult to reduce and inactive in Fischer–Tropsch synthesis were not generated. The dry coated catalysts exhibited comparable catalytic performance in Fischer–Tropsch synthesis to conventional chemical impregnated catalysts.