Heterogeneous Adsorption and Local Ordering of Formate on a Magnetite Surface.

Autor:	Creutzburg M; DESY NanoLab, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.; Department of Physics, University of Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany., Sellschopp K; Institute of Advanced Ceramics, Hamburg University of Technology (TUHH), Denickestraße 15, 21073 Hamburg, Germany., Tober S; DESY NanoLab, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.; Department of Physics, University of Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany., Grånäs E; DESY NanoLab, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany., Vonk V; DESY NanoLab, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany., Mayr-Schmölzer W; Institute of Advanced Ceramics, Hamburg University of Technology (TUHH), Denickestraße 15, 21073 Hamburg, Germany., Müller S; Institute of Advanced Ceramics, Hamburg University of Technology (TUHH), Denickestraße 15, 21073 Hamburg, Germany., Noei H; DESY NanoLab, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany., Vonbun-Feldbauer GB; Institute of Advanced Ceramics, Hamburg University of Technology (TUHH), Denickestraße 15, 21073 Hamburg, Germany., Stierle A; DESY NanoLab, Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany.; Department of Physics, University of Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany.
Jazyk:	angličtina
Zdroj:	The journal of physical chemistry letters [J Phys Chem Lett] 2021 Apr 22; Vol. 12 (15), pp. 3847-3852. Date of Electronic Publication: 2021 Apr 14.
DOI:	10.1021/acs.jpclett.1c00209
Abstrakt:	We report a novel heterogeneous adsorption mechanism of formic acid on the magnetite (111) surface. Our experimental results and density functional theory (DFT) calculations give evidence for dissociative adsorption of formic acid in quasibidentate and chelating geometries. The latter is induced by the presence of iron vacancies at the surface, making oxygen atoms accessible for hydrogen atoms from dissociated formic acid. DFT calculations predict that both adsorption geometries are energetically favorable under our experimental conditions. The calculations prove that the locally observed (√3 × √3) R 30° superstructure consists of three formate molecules in a triangular arrangement, adsorbed predominantly in a chelating geometry. The results show how defects can stabilize alternative adsorption geometries, which is a crucial ingredient for a detailed atomistic understanding of reaction barriers on magnetite and other oxide surfaces, as well as for the stability of carboxylic acid based nanocomposite materials.
Databáze:	MEDLINE
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