SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 60: Solid-Liquid Interfaces I: Structure and Spectroscopy
O 60.9: Vortrag
Mittwoch, 29. März 2023, 17:00–17:15, TRE Phy
Non-Random Island Nucleation in the Electrochemical Roughening on Pt(111) — •Marcel Rost1, Leon Jacobse2, and Marc Koper3 — 1Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands — 2Centre for X-ray and Nano Science CXNS, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg, Germany — 3Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
Many chemical surface systems develop ordered nano-islands during repeated reaction and restoration. Platinum is used in electrochemical energy applications, like fuel cells and electrolysers, although it is scarce, expensive, and degrades.
During oxidation-reduction cycles, simulating device operation, nucleation and growth of nano-islands occurs that eventually enhances the dissolution. Preventing nucleation would be the most effective solution. However, little is known about the atomic details of the nucleation; a process almost impossible to observe.
Here, we analyze the nuclei-distance distribution mapping out the underlying atomic mechanism: a rarely observed, non-random nucleation takes place. Special, preferential nucleation sites that a priori do not exist, develop initially via a precursor and eventually form a semi-ordered Pt-oxide structure.
This precursor mechanism seems to be general, possibly explaining also the nano-island formation on other surfaces/reactions.