SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 80: Poster Session VI: Poster to Mini-Symposium: Electrified solid-liquid interfaces I
O 80.7: Poster
Mittwoch, 3. März 2021, 13:30–15:30, P
We hold these truths to be self-evident, that all halide CVs are created equal. — •Nicolas G. Hörmann1,2 and Karsten Reuter2 — 1Technische Universität München, Garching, Germany — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
Consistent with chemical intuition, the cyclic voltammograms (CVs) of Ag(111) in halide containing solutions are essentially identical for Cl, Br, and I, when simulated based on DFT calculations and the computational hydrogen electrode (CHE) approximation. Quite in contrast, experiments reveal significant differences in CV peak heights and shapes.
Here we show that the DFT results can be reconciled with experiment, when using a fully grand canonical description in an implicit solvent model that allows for capacitive charging [1]. It is thus only the latter and not the adsorption energetics at the potential of zero charge, that leads to the experimental variation in the CVs across the halide series. This finding is supported by a general analysis of the relation between grand canonical and CHE energetics, which in addition provides new insights into non-Nernstian behavior and the relevance of classical electrochemical concepts such as the electrosorption valency[2].
[1] N.G. Hörmann et al., J. Chem. Phys. 150, 041730 (2019). [2] N.G. Hörmann et al., npj Comput. Mater. 6, 136 (2020).