Geometric Factors in K and Al Promoting of the Fe/MgO Fischer-Tropsch Catalyst

Abstract

The activity of Kand Al-promoted Fe/MgO catalyst for Fischer-Tropsch synthesis was measured under atmospheric pressure, with the aim to determine the promoter's influence on the catalyst selectivity, particularly in terms of olefins and isomers of lower hydrocarbons. The results have been correlated to the data of a previous study on the same catalyst, made under elevated pressure and designed for the alcohol production. It has been concluded that the promoting effect of K should be attributed to a geometric influence rather than to electronic promotion. The influence of Al promoter manifests itself like the "skin effect", resulting in suppression of adsorption of both CO and H2.

Fischer-Tropsch synthesis nanostructured catalysts: understanding structural characteristics and catalytic reaction

“…In addition to SiO 2 , other oxides, including ZrO 2 , Al 2 O 3 [118], MgO [119], CeO 2 [120], or Nb 2 O 3 [121] were used as support. Wan et al studied the Fe-Al 2 O 3 interaction over the precipitated iron catalyst in a slurry reactor and concluded that alumina inhibited the weak H 2 adsorption on iron surface but favored strong H 2 adsorption [122].…”