Water Structures Reveal Local Hydrophobicity on the In2O3(111) Surface

Water Structures Reveal Local Hydrophobicity on the In2O3(111) Surface

Článek WoS

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 cel l 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 cel l is unfavorable for adsorption and remains water-free. The first water layer thus shows ordering into nanoscopic 3D water clusters separated by hydrophobic pockets.

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 cel l 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 cel l is unfavorable for adsorption and remains water-free. The first water layer thus shows ordering into nanoscopic 3D water clusters separated by hydrophobic pockets.

indium oxide; water adsorption; water on oxides; atomic force microscopy; temperature-programmed desorption; density functional theory; ab initio molecular dynamics simulations

indium oxide; water adsorption; water on oxides; atomic force microscopy; temperature-programmed desorption; density functional theory; ab initio molecular dynamics simulations

CHEN, H.; BLATNIK, M.; RITTERHOFF, C.; SOKOLOVIC, I.; MIRABELLA, F.; FRANCESCHI, G.; RIVA, M.; SCHMID, M.; ČECHAL, J.; MEYER, B.; DIEBOLD, U.; WAGNER, M.

2023

27.12.2022

AMER CHEMICAL SOC

WASHINGTON

1936-086X

ACS Nano

16

12

Spojené státy americké

21163

21173

11

https://pubs.acs.org/doi/10.1021/acsnano.2c09115