Water-Hydroxyl Wetting Monolayer Predicted and Realized on a Hydrophobic Metal Surface

Water adsorption on metal surfaces is ubiquitous in broad natural and technological settings. However, elucidating this phenomenon is often challenging due to difficulties in accurately determining the morphology and understanding the chemistry of adsorbed water networks. Here, we report a significant discovery of the water-hydroxyl (H₂O–OH) wetting monolayer, which has long been deemed possible only on hydrophilic metal surfaces, now realized on an archetypal hydrophobic metal surface, Ag(111). Ab initio structure searches predicted a hexagonal hydrogen-bonded network comprising alternating H₂O and OH units; ensuing low-energy-electron-assisted synthesis in concert with extensive characterization and computational simulation provided compelling evidence of an H₂O–OH monolayer realized on the Ag(111) surface, with remarkable stability up to near room temperature. Our finding brings new insights into the intriguing chemistry of H₂O–OH overlayers on metal surfaces, and the electron-assisted synthesis opens a unique pathway toward creating delicate molecular networks.