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

Abstract

It is shown that the Fischer–Tropsch synthesis in the presence of Co–xMn/SiO2 cobalt catalysts with a manganese content of 0.5–2 wt % is characterized by high activity and C5+ 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 xCo3O4–(1−x)Mn3O4 type is confirmed. The relationship between the promoting effect of manganese and the structure of active sites and the character of adsorption of H2 and CO on the surface of the catalysts is ascertained.