The structure of mixed H2O-OH monolayer films on Ru(0001)

M. Tatarkhanov, E. Fomin, M. Salmeron, Klas Jerker Andersson, H. Ogasawara, L.G.M. Pettersson, A. Nilsson, J.I. Cerda

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Abstract

Scanning tunneling microscopy (STM) and x-ray absorption spectroscopy (XAS) have been used to study the structures produced by water on Ru(0001) at temperatures above 140 K. It was found that while undissociated water layers are metastable below 140 K, heating above this temperature produces drastic transformations, whereby a fraction of the water molecules partially dissociate and form mixed H2O-OH structures. X-ray photoelectron spectroscopy and XAS revealed the presence of hydroxyl groups with their O-H bond essentially parallel to the surface. STM images show that the mixed H2O-OH structures consist of long narrow stripes aligned with the three crystallographic directions perpendicular to the close-packed atomic rows of the Ru(0001) substrate. The internal structure of the stripes is a honeycomb network of H-bonded water and hydroxyl species. We found that the metastable low temperature molecular phase can also be converted to a mixed H2O-OH phase through excitation by the tunneling electrons when their energy is 0.5 eV or higher above the Fermi level. Structural models based on the STM images were used for density functional theory optimizations of the stripe geometry. The optimized geometry was then utilized to calculate STM images for comparison with the experiment.
Original languageEnglish
JournalJournal of Chemical Physics
Volume129
Issue number15
Pages (from-to)154109
ISSN0021-9606
DOIs
Publication statusPublished - 2008

Bibliographical note

Copyright (2008) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

Keywords

  • RUTHENIUM
  • PT(111)
  • PLATINUM
  • LIQUID WATER
  • HYDROGEN
  • ELECTROOXIDATION
  • ADSORPTION
  • SURFACES
  • SCANNING-TUNNELING-MICROSCOPY
  • HYDROXYL

Cite this

Tatarkhanov, M., Fomin, E., Salmeron, M., Andersson, K. J., Ogasawara, H., Pettersson, L. G. M., Nilsson, A., & Cerda, J. I. (2008). The structure of mixed H2O-OH monolayer films on Ru(0001). Journal of Chemical Physics, 129(15), 154109. https://doi.org/10.1063/1.2988903