Carburization of the Fe3O4(111) surface

The structures and energies of the stepwise carburized Fe-tet1- and Fe-oct2-terminated Fe3O4(111) surfaces have been computed at the level of density functional theory. Carburization of both surfaces is favored thermodynamically, and these results agree with the experimental findings. It is to note that the Fe-tet1-ten-ninated Fe3O4(111) surface has weak coverage effects, while the Fe-oct2-terminated Fe3O4(111) surface has strong coverage effects. On the basis of the calculated free energies of equilibrium, the carburization ability shows the order of C > CH > CH2 > CH3 > CO.