).
Institut für Angewandte Physik,
TU Wien, 1040 Wien, Austria
Faculty of Physics, Center for Computational Materials Science, University of Vienna, 1090 Wien, Austria
GeoRessources, Université de Lorraine, CNRS, 54000, Nancy, France
Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy
Understanding how the physical and electronic structures of metal-oxide surfaces evolve under varying conditions is crucial for optimizing their performance in applications such as catalysis. In this study, we compute the surface phase diagram of the Fe3O4(001) facet using density functional theory (DFT)-based calculations, with an emphasis on understanding the terminations observed in surface science experiments. Our results reveal two stable terminations in addition to the subsurface cation vacancy (SCV) structure, which dominates under oxidizing conditions. The commonly reported octahedral Fe pair, also known as the Fe-dimer termination, is stable within an oxygen chemical potential range of −3.1 eV < μO < −2.3 eV. We identify the lowest-energy structure of this surface as the one proposed by J. R. Rustad, E. Wasserman and A. R. Felmy, A Molecular Dynamics Investigation of Surface Reconstruction on Magnetite (001), Surf. Sci., 1999, 432, L583, where a tetrahedrally coordinated FeA atom is replaced by two octahedrally coordinated FeB atoms in the surface layer. This transformation serves as a precursor to the emergence of an FeO-like termination under highly reducing conditions. A key insight from our study is the importance of thoroughly sampling different charge-order configurations to identify the global minima across varying stoichiometries.
Corresponding author: Gareth S. Parkinson (parkinson).
You can download a PDF file of this open-access article from RSC Applied Interfaces or from the IAP/TU Wien web server.