Theoretical Study of CO Adsorption and Activation on Orthorhombic Fe7C3(001) Surfaces for Fischer–Tropsch Synthesis Using Density Functional Theory Calculations

Fischer–Tropsch synthesis (FTS), which converts CO and H2 into useful hydrocarbon products, has attracted considerable attention as an efficient method to replace crude oil resources. Fe-based catalysts are mainly used in industrial FTS, Fe7C3 is a common carbide phase the FTS reaction. However, intrinsic catalytic properties of theoretically unknown. Therefore, first attempt understand reaction on Fe7C3, direct CO* dissociation orthorhombic Fe7C3(001) (o-Fe7C3(001)) surfaces was studied using density functional theory (DFT) calculations. The surface energies 14 terminations o-Fe7C3(001) were compared, results showed that (001)0.20 most thermodynamically stable termination. Furthermore, effect C atom coverage activation, C–O bond performed o-Fe7C3(001)0.85, (001)0.13, (001)0.20, (001)0.09, (001)0.99 surfaces, where coverages 0.00, 0.17, 0.33, 0.60, respectively. activation linearly decreased increased. it can be concluded thermodynamic kinetic selectivity toward increased when had more C* vacancies.