SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 8: Poster Session I: Solid-liquid interfaces: Structure, spectroscopy
O 8.6: Poster
Montag, 1. März 2021, 10:30–12:30, P
Solving Catalyst Degradation: Platinum Stability for Fuel Cell Operation — •Francesc Valls Mascaró1, Marc T. M. Koper1, and Marcel J. Rost2 — 1Leiden Institute of Chemistry, Leiden University — 2Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University
The longevity of a catalyst plays a crucial role for many industrial scale applications. Platinum is the best candidate to be used in electrochemical energy conversion systems due to its high activity. However, platinum suffers from degradation during fuel cell operation. This degradation is caused by the nucleation and growth of nanoislands, which roughen the surface [1, 2]. It is known that the extend of this roughening can be tuned by including additives, changing the electrolyte pH or working within different potential windows [3, 4]. In this work, we study the degradation of different platinum stepped surfaces under potential cycling to oxidative potentials. Interestingly, we quantify significantly less degradation for the surfaces with shorter terraces: Pt(111) > Pt(15 15 14) > Pt(554). We present here a model that explains this trend, in which steps act like sinks for both adatoms and vacancies, slowering down the nucleation and growth of the mentioned nanoislands. Finally, we do not observe roughening at all for platinum surfaces with only four atoms terrace width: Pt(553) and Pt(533).
[1] Jacobse, L. et al., ACS Cent. Sci. 5 (12), 1920 (2019)
[2] Rost, M.J. et al., Nat. Commun. 10, 5233 (2019)
[3] Topalov, A. et al., J. Chem. Sci., 5, 631 (2014)
[4] Ruge, M. et al., J. Am. Chem. Soc., 139, 4532 (2017)