Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Solid-liquid interfaces: Reactions and electrochemisty I (joint session O/CPP)
O 17.4: Vortrag
Montag, 12. März 2018, 15:45–16:00, MA 144
The Reactivity of Individual ‘Defect’-Sites on Electrochemically Roughened Pt(111) — •Leon Jacobse1, Marcel J. Rost2, and Marc T.M. Koper1 — 1Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands — 2Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
Platinum is arguably the most stable, highly active electrocatalyst under oxidizing conditions in acidic media. Nonetheless, the poorly understood electrode degradation process strongly limits the economic feasibility of large scale applications.
Previously, we have shown by combination of simultaneous cyclic voltammetry and in-situ EC-STM that the total electrochemical signal of Pt(111) is directly correlated to its surface roughness [1]. This analysis, however, did not yet provide a rationale for this correlation. A detailed analysis of the EC-STM images provides information on the atomic-scale structure of the formed Pt nano-islands and their evolution. Correlating the resulting density of specific surface sites to the different hydrogen adsorption features in the voltammetry, allows us to determine the electrochemical reactivity of formed step and kink sites on the roughened surface. This finally delivers an insight on how to describe the electrochemical reactivity not only of the observed nano-islands but also of Pt nanoparticles in general.
[1] L. Jacobse, Y.-F. Huang, M.T.M. Koper, M.J. Rost, Nature Materials, accepted (2017)