| Catalysts were prepared by decomposing Fe(CO)(,5) (carbonyl derived catalysts, CDCs) and Fe(NO(,3))(,3) (a conventionally prepared catalyst, CPC) on (gamma)-alumina and were characterized by hydrogen adsorption, oxygen titration, Mossbauer spectroscopy and CO-TPD. CO hydrogenation activity and selectivity properties of these catalysts were measured at 473-513 K and 1 atm with H(,2)/CO ratios of 2 and 3.; The data provide evidence for decoration of metal crystallites on the CPC by either support moieties or partially reduced metal oxides. Dispersions of the CDCs were varied by either changing the metal loading (on a support dehydroxylated at 923K) or by changing dehydroxylation temperature (ca. 4.5 (wt)% metal loading). The absence of change in TOFs and selectivities with weight loading (or %D) suggests structure insensitivity while an order of magnitude change in activity with extent of dehydroxylation indicate that CO hydrogenation on Fe/alumina is more sensitive to the chemical environment of the reduced metal than its particle size. |
