Structure and Bonding of the Water−Hydroxyl Mixed Phase on Pt(111)

• Published in: Journal of physical chemistry. C Vol. 111; no. 41; pp. 15003 - 15012
• Main Authors: Schiros, T., Näslund, L.-Å., Andersson, K., Gyllenpalm, J., Karlberg, G. S., Odelius, M., Ogasawara, H., Pettersson, L. G. M., Nilsson, A.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 18.10.2007
• Subjects: ADSORBATES; ADSORPTION; APPROXIMATION; CORE-LEVEL; DENSITY-FUNCTIONAL THEORY; LIQUID WATER; OVERLAYER; OXYGEN; RAY-ABSORPTION-SPECTRA; SPECTROSCOPY; SURFACE
• ISSN: 1932-7447; 1932-7455; 1932-7455
• DOI: 10.1021/jp073405f

We combine low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and Auger electron spectroscopy (AES) with density functional theory (DFT) to reveal the structure and bonding of water−hydroxyl mixed layers adsorbed on Pt(111). We find that the stable water−hydroxyl adlayer forms a mixed phase of nearly coplanar hexamer structures resulting in (√3 × √3)R30° and (3 × 3) unit cells, respectively. In the asymmetric (3 × 3) structure the lateral O−O distances alternate between long and short bond lengths similar to the chemical bonding network for OH- ions in solution. The chemical driving force behind this similarity is discussed in a molecular orbital picture.