Adsorption of oleic acid on magnetite facets.

Autor: Creutzburg M; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany., Konuk M; Institute of Polymers and Composites, Hamburg University of Technology, Denickestr. 15, 21073, Hamburg, Germany., Tober S; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.; Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany., Chung S; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany., Arndt B; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany., Noei H; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany., Meißner RH; Institute of Polymers and Composites, Hamburg University of Technology, Denickestr. 15, 21073, Hamburg, Germany. robert.meissner@tuhh.de.; Institute of Surface Science, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502, Geesthacht, Germany. robert.meissner@tuhh.de., Stierle A; Centre for X-Ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany. andreas.stierle@desy.de.; Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany. andreas.stierle@desy.de.
Jazyk: angličtina
Zdroj: Communications chemistry [Commun Chem] 2022 Oct 23; Vol. 5 (1), pp. 134. Date of Electronic Publication: 2022 Oct 23.
DOI: 10.1038/s42004-022-00741-0
Abstrakt: The microscopic understanding of the atomic structure and interaction at carboxylic acid/oxide interfaces is an important step towards tailoring the mechanical properties of nanocomposite materials assembled from metal oxide nanoparticles functionalized by organic molecules. We have studied the adsorption of oleic acid (C 17 H 33 COOH) on the most prominent magnetite (001) and (111) crystal facets at room temperature using low energy electron diffraction, surface X-ray diffraction and infrared vibrational spectroscopy complemented with molecular dynamics simulations used to infer specific hydrogen bonding motifs between oleic acid and oleate. Our experimental and theoretical results give evidence that oleic acid adsorbs dissociatively on both facets at lower coverages. At higher coverages, the more pronounced molecular adsorption causes hydrogen bond formation between the carboxylic groups, leading to a more upright orientation of the molecules on the (111) facet in conjunction with the formation of a denser layer, as compared to the (001) facet. This is evidenced by the C=O double bond infrared line shape, in depth molecular dynamics bond angle orientation and hydrogen bond analysis, as well as X-ray reflectivity layer electron density profile determination. Such a higher density can explain the higher mechanical strength of nanocomposite materials based on magnetite nanoparticles with larger (111) facets.
(© 2022. The Author(s).)
Databáze: MEDLINE
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