Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 119: Oxides III: Single-Atom Catalysis, Iron Oxides
O 119.6: Talk
Friday, March 20, 2020, 12:00–12:15, REC C 213
Formic acid induced superstructure formation on magnetite (111) — •Marcus Creutzburg1,2, Heshmat Noei1, Björn Arndt1,2, Vedran Vonk1, Elin Grånäs1, Kai Sellschopp3, Gregor Vonbun-Feldbauer3, and Andreas Stierle1,2 — 1DESY NanoLab, Deutsches Elektronen-Synchrotron, Hamburg — 2Fachbereich Physik, Universität Hamburg — 3Institute of Advanced Ceramics, Hamburg University of Technology
Magnetite (Fe3O4) is an important and diverse transition metal oxide with applications as a catalyst in various industrial processes such as the water-gas shift reaction [1]. In material science magnetite nanoparticles are linked by oleic acid to form supercrystals with exceptional mechanical properties [2]. However, the oxide/carboxylic acid interface is not fully understood. In this contribution the adsorption of formic acid on the magnetite (111) single crystal surface is studied under UHV conditions at room temperature. Formic acid dissociates upon adsorption and forms a (√3×√3) R 30∘ superstructure, which is investigated using low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). Fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS) results indicate two different formic acid adsorption sites. Density functional theory (DFT) calculations of the two adsorption structures prove that both configurations form the superstructure and are the most stable under our experimental working conditions.
[1] M. Zhu et al., ACS Catalysis. 6, 722-732 (2016).
[2] A. Dreyer et al., Nature Materials 15, 522-528 (2016)