[Zurück]

Z. Jakub, M. Meier, F. Kraushofer, J. Balajka, J. Pavelec, M. Schmid, C. Franchini, U. Diebold, G. Parkinson:
"Rapid oxygen exchange between hematite and water vapor";
Nature Communications, 12 (2021), S. 64881 - 64888.

ARTICLE
Rapid oxygen exchange between hematite and
water vapor
Zdenek Jakub1,4, Matthias Meier 1,2, Florian Kraushofer 1, Jan Balajka 1, Jiri Pavelec 1, Michael Schmid1,
Cesare Franchini 2,3, Ulrike Diebold 1 & Gareth S. Parkinson 1 ✉
Oxygen exchange at oxide/liquid and oxide/gas interfaces is important in technology and
environmental studies, as it is closely linked to both catalytic activity and material degra-

dation. The atomic-scale details are mostly unknown, however, and are often ascribed to

poorly defined defects in the crystal lattice. Here we show that even thermodynamically
stable, well-ordered surfaces can be surprisingly reactive. Specifically, we show that all the
3-fold coordinated lattice oxygen atoms on a defect-free single-crystalline "r-cut"(1 102)
surface of hematite (α-Fe2O3) are exchanged with oxygen from surrounding water vapor
within minutes at temperatures below 70 °C, while the atomic-scale surface structure is

unperturbed by the process. A similar behavior is observed after liquid-water exposure, but

the experimental data clearly show most of the exchange happens during desorption of the

final monolayer, not during immersion. Density functional theory computations show that the
exchange can happen during on-surface diffusion, where the cost of the lattice oxygen

extraction is compensated by the stability of an HO-HOH-OH complex. Such insights into

lattice oxygen stability are highly relevant for many research fields ranging from catalysis and
hydrogen production to geochemistry and paleoclimatology.

http://dx.doi.org/10.1038/s41467-021-26601-4