Water Formation under Silica Thin Films: Real-Time Observation of a Chemical Reaction in a Physically Confined Space

Mauricio J. Prieto, Hagen W. Klemm, Feng Xiong, Daniel M. Gottlob, Dietrich Menzel, Thomas Schmidt, Hans Joachim Freund

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Using low-energy electron microscopy and local photoelectron spectroscopy, water formation from adsorbed O and H2 on a Ru(0001) surface covered with a vitreous SiO2 bilayer (BL) was investigated and compared to the same reaction on bare Ru(0001). In both cases the reaction is characterized by moving reaction fronts. The reason for this might be related to the requirement of site release by O adatoms for further H2-dissociative adsorption. Apparent activation energies ((Eapp a)) are found for the front motion of 0.59 eV without cover and 0.27 eV under cover. We suggest that the smaller activation energy but higher reaction temperature for the reaction on the SiO2 BL covered Ru(0001) surface is due to a change of the rate-determining step. Other possible effects of the cover are discussed. Our results give the first values for Eapp a in confined space.

Original languageEnglish
Pages (from-to)8749-8753
Number of pages5
JournalAngewandte Chemie International Edition in English
Volume57
Issue number28
DOIs
StatePublished - 9 Jul 2018

Keywords

  • LEEM
  • confined chemistry
  • heterogeneous catalysis
  • hydrogen oxidation
  • model systems

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