Density functional theory study on the interaction of CO with the Fe3O4(0 0 1) surface.

The adsorption properties of CO on the nondefective and defective (with an oxygen vacancy) B-layer Fe 3 O 4 (0 0 1) surfaces (an octahedral environment of iron ions) at different coverages are studied using the spin-polarized density functional theory with the inclusion of on-site Coulomb interaction by introducing Hubbard U parameter (DFT + U) method. It is found that the CO adsorption energy in general increases with the CO coverage. Both types of B-layer Fe 3 O 4 (0 0 1) surfaces have the excellent ability for CO oxidation. Comparatively, the defective B-layer Fe 3 O 4 (0 0 1) surface has a much stronger CO adsorption ability and a lower CO oxidation ability than the nondefective B-layer Fe 3 O 4 (0 0 1) surface. The density of state reveals the bonding mechanism of CO on the two surfaces. The effects of the ambient conditions on the CO adsorption processes are analyzed. [ABSTRACT FROM AUTHOR]