The structure of Mn3O4 (110) thin films

In this work, we examined the structure of Mn3O4 (110) thin films. Generally, Mn3+ and Mn2+ cation ratios on manganese oxide surfaces are expected to contribute to the catalytic activity of Mn3O4. However, the thermodynamically stable Mn3O4 (hausmannite) surface structure is not fully understood. Therefore, we investigated Mn3O4 films on Cu(111) combining X-ray photoelectron spectroscopy, low energy electron diffraction, scanning transmission electron microscopy, and scanning tunneling microscopy. Our results suggest a termination layer of Mn3O4 (110) film with a fully oxidized Mn2+ layer for the topmost surface and Mn3+ cations at the interface with Cu(111). The Mn3O4 (110) surface undergoes lattice distortions that may affect its chemical and physical properties known to be relevant for surface reactivity.