Carbon-containing materials such as coal and biomass may be processed to syngas, which can be further converted to ethylene, propylene and butylenes directly or indirectly. Potassium-promoted iron catalysts, loaded over high temperature annealed supports ZnAl6O10 and ZnAl10O16, are developed and compared with other reference catalysts. All catalysts were investigated by XRD, ICP, nitrogen physisorption, FESEM, CO2-TPD, and direct Fischer-Tropsch to light alkenes (FTO) reaction tests. Without the assistance of any surface modifier or molecular sieve, at a total pressure of 2 MPa (asymptotic to 20 bar), catalyst Fe/K/ZnAl6O10 reached a C-2(=)-C-4(=) hydrocarbon selectivity of 70%, which is one of the highest light alkene selectivity values documented for iron-based FTO catalysts. Relationships between characterization data and catalytic performance were discussed.