Density functional theory study on the interaction of CO₂ with Fe₃O₄(111) surface

Highlights: • Carbon dioxide is activated when absorption on the Fe₃O₄(111) surface. • Fe_oct2-tet1- terminated Fe₃O₄(111) surface is more active than Fe_tet1-terminated surface. • CO₂ serves as a charge acceptor to withdraw electrons from the Fe₃O₄(111) surface. • Covalent bonds is formed between the C atom of CO₂ and the surface O atoms. - Abstract: CO₂ adsorption on the Fe_tet1- and Fe_oct2-tet1-terminated Fe₃O₄(111) surface was investigated in order to understand the adsorption mechanism of CO₂ by using density functional theory (DFT). Both weak and strong adsorptions exist between the CO₂ and the Fe₃O₄(111) surface. The preferred adsorption site was found to be the O_d site on the Fe_oct2-tet1-termination, after adsorption, the CO₂ molecule was bent and the C−O bond was elongated, indicating the activation of CO₂. And it is found that Fe_oct2-tet1-terminated Fe₃O₄(111) surface is more active than Fe_tet1-terminated surface, CO₂ serves as a charge acceptor to withdraw electrons from the Fe_oct2-tet1-terminated Fe₃O₄(111) surface. In addition, partial density of states, electron localization function and difference electron density reveal that covalent bond was formed between the C atom of CO₂ and the surface O atom. These results provide fundamental insight into the CO₂ adsorption mechanism on Fe₃O₄(111) surface and potential application on the activation of CO₂.