Manganese promotion in cobalt-based Fischer-Tropsch catalysis

The effect of Mn addition on the catalytic performances of Fischer-Tropsch synthesis was investigated using a series of Co/TiO2 catalysts prepared by two different preparation methods; incipient wetness impregnation (IWI) and homogeneous deposition precipitation (HDP). Mn was loaded using two different procedures in order to investigate its interaction with Co and TiO2. Several characterization techniques, mainly XRD, XPS and TPR, were used to elucidate the Co oxidation state and dispersion and to estimate the Mn location. Fischer-Tropsch synthesis carried out at 1 bar of pressure showed an improvement of the catalytic performance in the Mn-promoted HDP catalyst, whereas no promotion effect was found in Mn-promoted IWI catalyst. This difference can be explained by a different Co-Mn interaction.