SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 106: Poster Session VIII: Poster to Mini-Symposium: Electrified solid-liquid interfaces III
O 106.4: Poster
Donnerstag, 4. März 2021, 13:30–15:30, P
Tuning the Stability of Platinum by means of Scan Rate — •Jon Bjarke Valbaek Mygind1, Francesc Valls Mascaro1, Marc T.M. Koper1, and Marcel J. Rost2 — 1Leiden Institute of Chemistry, Leiden University — 2Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University
Platinum is widely used as an electrocatalyst in several applications like fuel cells and electrolysers, due to its high catalytic activity. However, platinum is scarce and its industrial feasibility is limited by its degradation under oxidizing conditions. Repeated oxidation and reduction of a platinum electrode leads to the roughening of the surface, caused by the nucleation and growth of nano-islands, which first grow laterally (2D) and then in height (3D) [1]. The nucleation and growth of these islands is promoted by the creation of adatom vacancy pairs [2,3]. Unfortunately, the precise mechanism responsible for this process is still not fully understood. Here, we examine the growth rate of the roughness on a Pt(111) surface by analysing cyclic voltammograms at different sweep rates. From our understanding of surface growth, we have indications that the mechanism responsible for the creation of adatom-vacancy pairs is kinetically (surface diffusion) limited. At faster sweep rate, less roughening is observed, which could be explained by fewer adatoms and vacancies being created on the surface, supporting our hypothesis.
[1] Jacobse L. et al., ACS Cent. Sci. 5 (12), 1920 (2019)
[2] Rost, M.J. et al., M.T.M., Nat. Commun. 10, 5233 (2019)
[3] Ruge, M. et al., J. Am. Chem. Soc., 139, 4532-4539 (2017)