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

doi:10.1002/anie.201802000

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

Chair of Experimental Physics

Research output: Contribution to journal › Article › peer-review

41 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 ((E^app _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 E^app _a in confined space.

Original language	English
Pages (from-to)	8749-8753
Number of pages	5
Journal	Angewandte Chemie International Edition in English
Volume	57
Issue number	28
DOIs	https://doi.org/10.1002/anie.201802000
State	Published - 9 Jul 2018

Keywords

LEEM
confined chemistry
heterogeneous catalysis
hydrogen oxidation
model systems

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

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.",

keywords = "LEEM, confined chemistry, heterogeneous catalysis, hydrogen oxidation, model systems",

author = "Prieto, {Mauricio J.} and Klemm, {Hagen W.} and Feng Xiong and Gottlob, {Daniel M.} and Dietrich Menzel and Thomas Schmidt and Freund, {Hans Joachim}",

note = "Publisher Copyright: {\textcopyright} 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.",

year = "2018",

month = jul,

day = "9",

doi = "10.1002/anie.201802000",

language = "English",

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journal = "Angewandte Chemie International Edition in English",

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T1 - Water Formation under Silica Thin Films

T2 - Real-Time Observation of a Chemical Reaction in a Physically Confined Space

AU - Prieto, Mauricio J.

AU - Klemm, Hagen W.

AU - Xiong, Feng

AU - Gottlob, Daniel M.

AU - Menzel, Dietrich

AU - Schmidt, Thomas

AU - Freund, Hans Joachim

PY - 2018/7/9

Y1 - 2018/7/9

N2 - 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.

AB - 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.

KW - LEEM

KW - confined chemistry

KW - heterogeneous catalysis

KW - hydrogen oxidation

KW - model systems

UR - http://www.scopus.com/inward/record.url?scp=85049571763&partnerID=8YFLogxK

U2 - 10.1002/anie.201802000

DO - 10.1002/anie.201802000

M3 - Article

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SN - 1433-7851

VL - 57

SP - 8749

EP - 8753

JO - Angewandte Chemie International Edition in English

JF - Angewandte Chemie International Edition in English

IS - 28

ER -

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

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