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DS: Fachverband Dünne Schichten
DS 31: Poster Session II
DS 31.9: Poster
Thursday, March 15, 2018, 11:15–13:15, Poster F
Well Ordered Iron Sulfide Layers on Au(111) — •Earl Davis, Giulia Berti, Helmut Kuhlenbeck, and Hans-Joachim Freund — Fritz-Haber-Institut der Max-Planck-Gesellschaft
The iron-sulfur world hypothesis of G. Wächtershäuser is an origin-of-life theory which proposes that early life may have formed at the surface of sub-marine iron sulfide compounds. This involves the activation of carbon dioxide to form simple organic molecules. Theoretical and experimental studies have shown that the mineral greigite (Fe3S4) should be active for this.
With the goal of CO2 activation, our aim was to prepare ordered iron sulfide layers. We found that such a layer can be prepared on Au(111) by deposition of iron in an atmosphere of S2 molecules which are produced by an electrochemical sulfur source. According to XPS, the layer is sulfur terminated, and STM shows a homogeneous, well-ordered surface with a hexagonal symmetry. The same symmetry is found in LEED patterns and the hexagonal lattice parameter fits to what is expected for Fe3S4(111). I/V LEED curves were measured in order to determine details of the structure. Additionally, initial reactivity experiments have shown that it is possible to hydrogenate the surface, which might offer routes to hydrogenation reactions.