Insight into the activation of CO2 and H2 on K2O-adsorbed Fe5C2(110) for olefins production: A density functional theory study

The activation of reactant molecules on catalyst surface plays critical roles in the catalytic reaction process. The activation of CO2 and H2 molecules on clean and K2O-adsorbed Fe5C2(110) were comparatively investigated via density functional theory (DFT) calculations to disclose the promoting effect of K2O on hydrogenation of CO2 to olefins. DFT calculations suggest that the adsorption of K2O helps to direct activation of CO2 to CO species, and then promote in-situ C-C* coupling of CO with surface carbon of chi-Fe5C2. The Fe-H bond from H2 dissociation on K2O-adsorbed Fe5C2(110) can lower the activity of H species, by which helps to avoid the over-hydrogenation of olefins to saturated alkanes. This study partially reveals the promoting effect of K2O on the activation of reactant molecules on chi-Fe5C2 surface, which is helpful to design new catalysts for CO2 conversion to value-added chemicals.