In situ EXAFS study of the bimetallic interaction in a rhenium-promoted alumina-supported cobalt Fischer-Tropsch catalyst

The local environments about the rhenium atoms in a Co-Re/gamma -Al2O3 cata lyst after different reduction periods have been studied by X-ray absorptio n spectroscopy (EXAFS). The bimetallic catalyst containing 4.6 wt% cobalt a nd 2 wt% rhenium has been compared with a corresponding monometallic sample with 2 wt% rhenium on the same support. The rhenium L-III EXAFS analysis s hows that bimetallic particles are formed after reduction at 450 degreesC w ith the average particle size being less than 15 Angstrom. More than 6 h re duction at 450 degreesC is required for complete reduction of accessible rh enium.