SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 96: Solid-Liquid Interfaces III: Reactions and Electrochemistry II
O 96.6: Vortrag
Freitag, 31. März 2023, 11:45–12:00, TRE Phy
Electrochemical Roughening of Stepped Platinum Surfaces — •Francesc Valls Mascaró1, Marc Koper1, and Marcel Rost2 — 1Leiden Institute of Chemistry, Leiden University — 2Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University
Platinum is the model catalyst to be used in electrochemical energy conversion devices due to its high activity. Nevertheless, its industrial applicability is limited, as it degradates during fuel cell operation. This has been extensively studied by Cyclic Voltammetry and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) [1, 2]. It is well known that this degradation is linked to the nucleation and growth of platinum nanoislands on initially atomically flat terraces [3, 4, 5, 6]. However, there is no insight yet on the role of steps on this roughening process. In this work, we combine Cyclic Voltammetry and Electrochemical Scanning Tunneling Microscopy to study the stability of different stepped platinum surfaces upon oxidation-reduction cycling. Surprisingly, the electrochemical results indicate that neither 2D nor 3D (for Pt(533)) and no 3D (for Pt(553)) roughness develops, although we clearly observe island formation in the STM, and thus an increase in the step lengths and roughness.
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