).
Institut für Angewandte Physik,
TU Wien, 1040 Wien, Austria
State Key Laboratory of Catalysis, Dalian
Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
University of the Chinese Academy of Sciences, Beijing 100049, China
University of the Chinese Academy of Sciences, Beijing 100049, China
Central European Institute of Technology (CEITEC), Brno University of Technology, 61200 Brno, Czech Republic
Interdisciplinary Center for Molecular Materials (ICMM) and Computer Chemistry Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91052 Erlangen, Germany
Clean oxide surfaces are generally hydrophilic. Water molecules anchor at undercoordinated surface metal atoms that act as Lewis acid sites, and they are stabilized by H bonds to undercoordinated surface oxygens. The large unit cell of In2O3(111) provides surface atoms in various configurations, which leads to chemical heterogeneity and a local deviation from this general rule. Experiments (TPD, XPS, nc-AFM) agree quantitatively with DFT calculations and show a series of distinct phases. The first three water molecules dissociate at one specific area of the unit cell and desorb above room temperature. The next three adsorb as molecules in the adjacent region. Three more water molecules rearrange this structure and an additional nine pile up above the OH groups. Despite offering undercoordinated In and O sites, the rest of the unit cell is unfavorable for adsorption and remains water-free. The first water layer thus shows ordering into nanoscopic 3D water clusters separated by hydrophobic pockets.
Corresponding author: Margareta Wagner (Wagner).
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