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O: Fachverband Oberflächenphysik

O 7: Poster Session I: Heterogeneous catalysis I

O 7.4: Poster

Monday, March 1, 2021, 10:30–12:30, P

The Water Forming Reaction on Palladium Nanoparticles Studied by Kelvin Probe Force Microscopy — Ali El Barraj, Baptiste Chatelain, and •Clemens Barth — Aix-Marseille University, CNRS, CINaM, 13288 Marseille, France

The adsorption of atomic or molecular species on metal nanoparticles (NP), the absorption of atomic species like carbon, hydrogen or oxygen inside NPs and chemical reactions at NPs are of key interest in heterogeneous catalysis. Such phenomena strongly depend on the NP*s size and shape so that a characterization at the single NP level is desired. A solution is to use Kelvin probe force microscopy (KPFM) and noncontact AFM (nc-AFM) in UHV. Because adsorbed or absorbed species almost always create a surface dipole, their presence can be directly put into evidence by measuring the change of work function (WF) of the NP as recently demonstrated with oxygen and PdNPs [1].

In this contribution, we show that KPFM can be used to monitor the O+H water forming reaction on PdNPs, which is of general importance in astrophysics and for fuel cells. We discuss the reaction itself but also phenomena, which involve possible subsurface oxygen creation and carbon de-activation.

[1] Grönbeck, H.; Barth, C. J. Phys. Chem. C 2019, 123, 24615–24625.