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Water Formation under Silica Thin Films: Real‐Time Observation of a Chemical Reaction in a Physically Confined Space
Author(s) -
Prieto Mauricio J.,
Klemm Hagen W.,
Xiong Feng,
Gottlob Daniel M.,
Menzel Dietrich,
Schmidt Thomas,
Freund HansJoachim
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201802000
Subject(s) - x ray photoelectron spectroscopy , adsorption , activation energy , reaction rate , bilayer , chemical reaction , low energy electron microscopy , chemistry , photoemission electron microscopy , cover (algebra) , front cover , analytical chemistry (journal) , materials science , electron microscope , catalysis , physics , optics , nuclear magnetic resonance , organic chemistry , biochemistry , membrane , engineering , mechanical engineering
Abstract Using low‐energy electron microscopy and local photoelectron spectroscopy, water formation from adsorbed O and H 2 on a Ru(0001) surface covered with a vitreous SiO 2 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 H 2 ‐dissociative adsorption. Apparent activation energies ( E a a p p ) 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 SiO 2 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 a a p pin confined space.