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O: Fachverband Oberflächenphysik
O 88: Poster Session VII: Oxides and insulators: Adsorption and reaction of small molecules I
O 88.6: Poster
Thursday, March 4, 2021, 10:30–12:30, P
Rapid surface oxygen exchange at the hematite-water interface — Zdenek Jakub1, Matthias Meier1, Florian Kraushofer1,2, Jan Balajka1, Jiri Pavelec1, Michael Schmid1, Cesare Franchini2,3, Ulrike Diebold1, and •Gareth S. Parkinson1 — 1TU Wien, Vienna, Austria — 2University of Vienna, Vienna, Austria — 3Universitá di Bologna, Bologna, Italy
It seems natural to assume that low-index surfaces of insoluble minerals do not exchange atoms with their surroundings. Here, we will show using surface science techniques that all oxygen atoms on the *r-cut* (1-102) surface are exchanged with oxygen from surrounding water vapour within minutes at temperatures below 70°C, even though the structure remains intact. Density functional theory computations suggest the oxygen exchange occurs during on-surface diffusion, and that cooperative stabilization of an HO-HOH-OH complex compensates the cost of the lattice oxygen extraction. Such a rapid oxygen exchange mechanism affects the isotope composition in the near-surface region, and the knowledge of the mineral-liquid interface dynamics is relevant for many fields ranging from hydrogen production to paleoclimatology.