Influence of Manganese on the Catalytic Properties and Structure of the Active Surface of a Cobalt Fischer–Tropsch Catalyst

It is shown that the Fischer–Tropsch synthesis in the presence of Co– x Mn/SiO 2 cobalt catalysts with a manganese content of 0.5–2 wt % is characterized by high activity and C 5+ hydrocarbon selectivity. The optimum concentration of manganese as a promoter is 1 wt %. The influence of manganese on the state of the surface of the catalysts in oxide and reduced forms is studied by a number of physicochemical methods. The formation of solid solutions of cobalt and manganese oxides of the x Co 3 O 4 –(1− x )Mn 3 O 4 type is confirmed. The relationship between the promoting effect of manganese and the structure of active sites and the character of adsorption of H 2 and CO on the surface of the catalysts is ascertained.