Crystalline Ice Growth on Pt(111): Observation of a Hydrophobic Water Monolayer

Abstract

The growth of crystalline water films on Pt(111) is investigated using rare gas physisorption. The water monolayer wets Pt(111) at all temperatures investigated (20-155 K). At low temperatures (T< or =120 K), additional water layers kinetically wet the monolayer surface. However, crystalline ice films grown at higher temperatures (T > 135 K) do not wet the water monolayer. These results are consistent with recent theory and experiments suggesting that the molecules in the water monolayer form a surface with no dangling OH bonds or lone pair electrons, giving rise to a hydrophobic water monolayer on Pt(111).

Water clustering on nanostructured iron oxide films

“…This result shows that the enhanced hydrophilicity conferred to the surface by the OH groups is lost after formation of the first H 2 O monolayer. This is similar to hydrophobic water layers studied previously on hydrophobic Pt(111) 49 and graphite 50 surfaces as well as on a hydrophilic kaolinite surface 51 . In all these cases, the preferential downward orientation of O-H bonds in the outermost water layers left surfaces devoid of 'dangling H-bonds' which could bind strongly to the next layer of water.…”

Tuning Hydrophobicity of Platinum by Small Changes in Surface Morphology

“…Also, minute details of the substrate appear to be of great relevance. A single molecular layer of amorphous solid water is hydrophilic [4], whereas the same layer of crystalline ice is hydrophobic [5].In this Letter, we show that a small change at the atomic level in substrate morphology without changing chemical identity or confinement size may also affect how water molecules adsorb to a surface. A switch from hydrophobic to hydrophilic behavior is not only apparent from drastic changes in H 2 O's desorption characteristics, but also in the chemical reactivity toward H-D exchange at well-ordered platinum surfaces.…”

“…Also, minute details of the substrate appear to be of great relevance. A single molecular layer of amorphous solid water is hydrophilic [4], whereas the same layer of crystalline ice is hydrophobic [5].…”

Desorption of H2O from Flat and Stepped Pt(111)

“…Only a single peak for the desorption of the monolayer is observed in several studies 13,11,14 at temperatures in the range of 160-170 K.…”

“…4 To reveal the underlying principles of the interaction of water with solid surfaces, numerous studies have been undertaken in recent years in which the interaction of H 2 O with model surfaces was studied using surface science methods. [5][6][7] An especially well studied system is the interaction of water with closely packed surfaces of noble or transition metals, the most prominent example being Pt(111) (see, e.g., refs [8][9][10][11][12][13][14][15].…”