Hydrophilic Interaction Between Low-Coordinated Au and Water: H2O/Au(310) Studied with TPD and XPS

In this work, we study the relatively weak H2O Au interaction on the highly stepped and anisotropic (310) surface with temperature-programmed desorption and X-ray photoelectron spectroscopy. Compared to Au(111), we report an enhanced adsorption energy of H2O-Au(310) as observed from the (sub)monolayer desorption peak. This peak shows zero-order desorption kinetics, which we do not explain with a typical two-phase coexistence model but rather by desorption from the ends of one-dimensional structures. These could cover both the steps and (part of) the terraces. We do not observe crystallization of ice clusters as observed on Au(111). This leads to the conclusion that this stepped surface forms a hydrophilic template for H2O adsorption. We also notice that the precise orientation of the steps determines the H2O binding strength. Despite the surface's enhanced H2O interaction, we do observe any significant H2O dissociation. This indicates that the presence of low-coordinated Au atoms is not enough to explain the role of H2O in Au catalysis.