Preparation of Fischer–Tropsch supported cobalt catalysts using a new gas anti-solvent process

Cobalt and ruthenium-promoted cobalt Fischer–Tropsch catalysts supported on titania have been prepared for the first time by gas anti-solvent precipitation. The use of dense CO2 as an anti-solvent enables the precipitation of cobalt acetate and ruthenium acetylacetonate onto preformed titania. The gas anti-solvent process produces catalysts with the desired 20 wt % cobalt content as precursors, which on calcination give highly dispersed Co3O4. The addition of ruthenium to the gas anti-solvent prepared cobalt catalysts has been investigated by two methods (a) coprecipitation with cobalt acetate and (b) wet impregnation onto a precalcined cobalt titania catalyst, and these resulted in catalysts with distinctly different properties. These catalysts were compared with a standard ruthenium-promoted cobalt catalyst prepared by wet impregnation and were found to be substantially more active for the Fischer–Tropsch reaction