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O: Fachverband Oberflächenphysik
O 54: Focus Session: Scanning Probe Microscopy with Quartz Sensors II
O 54.7: Talk
Wednesday, March 29, 2023, 17:00–17:15, CHE 89
Surface structure of dry and hydrated α-Al2O3(0001) — Johanna Hütner1, David Kugler1,2, Michael Schmid1, Ulrike Diebold1, and •Jan Balajka1 — 1Institute of Applied Physics, TU Wien, Vienna, Austria — 2CEITEC, Brno, Czech Republic
Corundum α-Al2O3 is an important ceramic also widely used as a support for heterogeneous catalysis. Due to similar Al coordination, α-Al2O3 is an important model system for naturally occurring minerals, such as aluminosilicate clays. Detailed studies of alumina surfaces have been stymied by its insulating nature but successfully performed with atomic force microscopy [1]. We used noncontact AFM to investigate the (√31×√31)R9∘-reconstructed Al2O3(0001) surface formed upon high-temperature annealing. The reactivity of surface sites is strongly affected by hydroxylation. However, complete surface hydroxylation requires high pressures of water vapor (1 Torr) [2] that cannot be easily achieved in a conventional ultrahigh vacuum system. We explored the interaction of the Al2O3(0001) surface with varying pressures of water vapor as well as ultrapure liquid water dosed with a UHV-compatible dispenser [3]. The results will provide new insights into the hydration of environmental substrates. [1] J. V. Lauritsen, et al., Phys. Rev. Lett. 103, 076103 (2009) [2] P. J. Eng, et al., Science 288, 1029 (2000) [3] J. Balajka, et al., Rev. Sci. Instrum. 89, 8, 083906 (2018)