Intrinsic disorder of dangling OH-bonds in the first water layer on noble metal surfaces

Using the first-principles calculation, we have systematically investigated the orientation of dangling OH-bonds in the first adsorbed water layer on close packed surface of noble metals (gold, platinum and palladium). We find that, the distribution of up and down dangling OH-bonds can strongly change the adsorption stability. A specific distribution of dangling OH-bonds is always indispensable in various adsorption patterns for its stability. The inplane arrangement of water molecules also has important influence on the orientation of dangling OH-bonds. More importantly, the disorder in the orientation (up or down) of dangling OH manifests a kind of zerotemperature residual entropy in some absorption structures. In essence, the residual entropy arises from the competition between water-water and water-metal interactions, which is different from the counterpart in ice crystals.

Automated summary

The study reveals that the orientation of dangling OH bonds in the first adsorbed water layer on noble metal surfaces plays a crucial role in adsorption stability. Specific distribution of these OH bonds is necessary for stability across various adsorption patterns. Additionally, the inplane arrangement of water molecules and the disorder in the orientation of dangling OH bonds contribute to a residual entropy in certain absorption structures, arising from competition between water-water and water-metal interactions.