AMaSiS 2021 - Abstract

Eikerling, Michael

Theory and computation of charged electrochemical interfaces

Forschungszentrum Jülich GmbH / Rheinisch-Westfälische Technische Hochschule Aachen, Germany

The region between charged metal surface and aqueous electrolyte lies at the heart of electrochemical energy technologies. The need to understand the properties of this region, which is also known as the electrochemical double layer (EDL), continues to drive extensive research in experiment and theory [1, 2]. The fundamental challenge is to disentangle the complex interplay of electronic structure effects, potential-induced variations of double layer structure and properties, local electrochemical conditions, and kinetics of vital electrocatalytic reactions. We will present a grand-canonical model that accounts for essential components and phenomena of the EDL [3, 4]. The hybrid density-potential functional is parametrized with quantum mechanical density functional theory (DFT) calculations, compared with experimental data, and employed to study interfacial electrochemical properties. In parallel, we have adopted a computational scheme that employs the DFT/ESM-RISM method, developed by Otani and co-workers [5], and applied it to simulate the Pt (111) surface with varying number of oxygen adatoms in acidic solution [6]. With some variation to the distance of closest approach between metal and electrolyte regions being done, the hybrid solvation method reproduced the peculiar non-monotonic charging relation of the Pt-electrolyte interface, in agreement with the theoretical prediction in Ref. [3]. The presentation will conclude with a discussion of practical implications of this charging relation.

References
[1] O.M. Magnussen and A. Gross, Toward an Atomic-Scale Understanding of Electrochemical Interface Structure and Dynamics, J. Am. Chem. Soc. 141, 4777-4790 (2019).
[2] M.J. Eslamibidgoli and M.H. Eikerling, Approaching the Self-consistency Challenge of Electrocatalysis with Theory and Computation, Current Opinion in Electrochemistry 9, 189-197 (2018).
[3] J. Huang, A. Malek, J. Zhang and M.H. Eikerling, Non-monotonic Surface Charging Behavior of Platinum: A Paradigm Change, J. Phys. Chem. C 120, 13587-13595 (2016).
[4] J. Huang, S. Chen, and M. Eikerling, Grand-Canonical Model of Electrochemical Double Layers from a Hybrid Density-Potential Functional, J. Chem. Theory Comput. 17, 2417-2430 (2021).
[5] S. Nishihara and M. Otani, Hybrid Solvation Models for Bulk, Interface, and Membrane: Reference Interaction Site Methods Coupled with Density Functional Theory, Phys. Rev. B 96, 115429 (2017).
[6] V.M. Fernandez-Alvarez and M.H. Eikerling, Interface Properties of the Partially Oxidized Pt(111) Surface Using Hybrid DFT-Solvation Models, ACS Appl. Mater. Interfaces 11, 43774-43780 (2019).