Jump to main content
Jump to site search

Issue 5, 2016
Previous Article Next Article

Electron stimulated hydroxylation of a metal supported silicate film

Author affiliations

Abstract

Water adsorption on a double-layer silicate film was studied by using infrared reflection–absorption spectroscopy, thermal desorption spectroscopy and scanning tunneling microscopy. Under vacuum conditions, small amounts of silanols (Si–OH) could only be formed upon deposition of an ice-like (amorphous solid water, ASW) film and subsequent heating to room temperature. Silanol coverage is considerably enhanced by low-energy electron irradiation of an ASW pre-covered silicate film. The degree of hydroxylation can be tuned by the irradiation parameters (beam energy, exposure) and the ASW film thickness. The results are consistent with a generally accepted picture that hydroxylation occurs through hydrolysis of siloxane (Si–O–Si) bonds in the silica network. Calculations using density functional theory show that this may happen on Si–O–Si bonds, which are either parallel (i.e., in the topmost silicate layer) or vertical to the film surface (i.e., connecting two silicate layers). In the latter case, the mechanism may additionally involve the reaction with a metal support underneath. The observed vibrational spectra are dominated by terminal silanol groups (ν(OD) band at 2763 cm−1) formed by hydrolysis of vertical Si–O–Si linkages. Film dehydroxylation fully occurs only upon heating to very high temperatures (∼1200 K) and is accompanied by substantial film restructuring, and even film dewetting upon cycling hydroxylation/dehydroxylation treatment.

Graphical abstract: Electron stimulated hydroxylation of a metal supported silicate film

Back to tab navigation

Supplementary files

Publication details

The article was received on 09 Nov 2015, accepted on 06 Jan 2016 and first published on 06 Jan 2016


Article type: Paper
DOI: 10.1039/C5CP06852E
Citation: Phys. Chem. Chem. Phys., 2016,18, 3755-3764
  • Open access: Creative Commons BY license
  •   Request permissions

    Electron stimulated hydroxylation of a metal supported silicate film

    X. Yu, E. Emmez, Q. Pan, B. Yang, S. Pomp, W. E. Kaden, M. Sterrer, S. Shaikhutdinov, H. Freund, I. Goikoetxea, R. Wlodarczyk and J. Sauer, Phys. Chem. Chem. Phys., 2016, 18, 3755
    DOI: 10.1039/C5CP06852E

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements