Combined EXAFS and STEM-EELS study of the electronic state and location of Mn as promoter in Co-based Fischer-Tropsch catalysts

STEM-EELS and EXAFS have been used to investigate the location and electronic state of Mn as promoter in TiO2- supported cobalt Fischer Tropsch catalysts prepared by two different procedures. It was found that the extent of interaction between Mn and the active Co phase as well as the level of Mn dispersion over the TiO2 surface largely determine the enhancement of the selectivity in the Fischer Tropsch synthesis at pressures of 1 bar.