Mechanistic study of CO2 hydrogenation on FeCu-K/Al2O3 and FeCu-K/CeO2 catalysts

Atmospheric carbon dioxide concentrations have been rapidly increasing due to fossil fuel combustion and industrial activities, posing a serious threat to the global climate. To address this challenge, catalytic CO 2 conversion to valuable chemicals has been widely studied. Reverse water gas shift (RWGS) reactions are a promising strategy for CO 2 utilization coupled with downstream hydrocarbon synthesis processes such as the Fischer-Tropsch (FT) reaction. In this study, we investigated the reaction mechanism of the initial stage of olefin formation on FeCu-K catalysts supported by Al 2 O 3 and CeO 2 using density functional theory (DFT) calculations, focusing on the key elementary steps of CO 2 hydrogenation and subsequent hydrocarbon production. Based on our mechanistic study, we identified the potential-determining step for CO 2 hydrogenation and C-C coupling reactions on FeCu/Al 2 O 3 and FeCu/CeO 2 catalysts, and the role of the promoter (K) in their catalytic activity and selectivity. Based on our electronic structure analysis, we also proposed electronegativity as a simple descriptor for predicting catalytic activity for CO 2 hydrogenation.