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