This work investigates the effects of potassium addition on light olefin production from CO2 hydrogenation over the Al2O3-supported Fe-Co bimetallic catalysts. The addition of small amount of K on the Fe-Co catalyst significantly enhanced C-2-C-4 olefin formation. The C-2-C-4 olefins predominated among C-2(+) hydrocarbons at K/Fe atomic ratio of 1. Temperature-programmed desorption experiments demonstrated that K addition diminished the weakly adsorbed hydrogen but enhanced CO2 adsorption on the catalyst surface, which led to significantly enhanced production of light olefins. For C-2-C-4 olefin synthesis at 573 K and 1.0 MPa, the K-promoted Fe-Co/Al2O3 catalyst also showed better performance than the K-promoted Fe-Mn/Al2O3 catalyst which is known as a good catalyst for olefin production, under the present conditions employed. The pathway of olefin formation from CO2 hydrogenation was analyzed. Light olefins were formed via two-step reactions over K-promoted Fe-Co catalysts with the formation of CO or CO-like intermediate as the first step. Some of these olefins could be further hydrogenated to paraffins, depending on the type and concentration of chemisorbed hydrogen on the catalyst surface. (C) 2015 Elsevier B.V. All rights reserved.