Oxidation mechanism and ferryl domain formation on the α-Fe2O3 (0001) surface

Recent experimental evidence calls for a reinterpretation of the oxidized structure in chemically distinct domains of the hematite (0001) surface as the ferryl (Fe=O) termination rather than the bulk terminated O-3-Fe-Fe-R structure. Although this interpretation is consistent with experimental data and ab initio thermodynamics calculations, it raises serious questions about how molecular oxygen can be dissociated on a surface where reactive iron centers are slightly more than 5 angstrom apart. Here, we propose a novel cooperative bimolecular mechanism that provides a reasonable pathway for the formation of the unusual ferryl surface termination and should be readily reversible, which is important for understanding the function of hematite surfaces as an oxidation catalyst. (c) 2007 Elsevier B.V. All rights reserved.