Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jul 9;57(28):8749-8753.
doi: 10.1002/anie.201802000. Epub 2018 Jun 6.

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

Mauricio J Prieto  1 , Hagen W Klemm  1 , Feng Xiong  2 , Daniel M Gottlob  1 , Dietrich Menzel  1   3 , Thomas Schmidt  1 , Hans-Joachim Freund  1
Affiliations

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

Mauricio J Prieto et al. Angew Chem Int Ed Engl. .

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 (Eaapp ) 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 Eaapp in confined space.

Keywords: LEEM; confined chemistry; heterogeneous catalysis; hydrogen oxidation; model systems.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Representation of the sample used to study the water formation reaction in the confined space under a vitreous SiO2 bilayer supported on Ru (0001).
Figure 1
Figure 1
Snapshots of the reaction front observed during annealing in 1×10−6 mbar H2 at 550 K. E kin=14 eV.
Figure 2
Figure 2
a) LEEM‐IV curves recorded at room temperature on different areas of the H2‐treated SiO2 vitreous BL on Ru(0001), as indicated by the inset. b) O 1s and Si 2p XPS spectra collected before and after H2 treatment. O 1s and Si 2p lines were measured with 600 eV and 175 eV, respectively.
Figure 3
Figure 3
Arrhenius plots of the temperature‐dependent velocities of the H2 oxidation front on SiO2/Ru(0001) (blue dots) and 3O/Ru(0001) (black dots).
See this image and copyright information in PMC

References

    1. None
    1. Li H., Xiao J., Fu Q., Bao X., Proc. Natl. Acad. Sci. USA 2017, 114, 5930–5934; - PMC - PubMed
    1. Emmez E., Anibal Boscoboinik J., Tenney S., Sutter P., Shaikhutdinov S., Freund H.-J., Surf. Sci. 2016, 646, 19–25;
    1. Emmez E., Yang B., Shaikhutdinov S., Freund H. J., J. Phys. Chem. C 2014, 118, 29034–29042.
    1. Miners S. A., Rance G. A., Khlobystov A. N., Chem. Commun. 2013, 49, 5586–5588. - PubMed

Publication types

LinkOut - more resources