Interface Properties of the Partially Oxidized Pt(111) Surface Using Hybrid DFT–Solvation Models

Peer reviewed: 
Yes, item is peer reviewed.
Scholarly level: 
Faculty/Staff
Final version published as: 

Fernandez-Alvarez V. M.; Eikerling M. H., ACS Appl. Mater. Interfaces 2019, Accepted. DOI: 10.1021/acsami.9b16326.

Date created: 
2019-10-25
Keywords: 
Ab initio simulations
Hybrid DFT methods
Electrocatalysis
Oxygen reduction reaction
Electrochemical interface
Abstract: 

This article reports a theoretical–computational effort to model the interface between an oxidized platinum surface and aqueous electrolyte. It strives to account for the impact of the electrode potential, formation of surface-bound oxygen species, orientational ordering of near-surface solvent molecules, and metal surface charging on the potential profile along the normal direction. The computational scheme is based on the DFT/ESM-RISM method to simulate the charged Pt(111) surface with varying number of oxygen adatoms in acidic solution. This hybrid solvation method is known to qualitatively reproduce bulk metal properties like the work function. However, the presented calculations reveal that vital interface properties such as the electrostatic potential at the outer Helmholtz plane are highly sensitive to the position of the metal surface slab relative to the DFT-RISM boundary region. Shifting the relative position of the slab also affects the free energy of the system. It follows that there is an optimal distance for the first solvent layer within the ESM-RISM framework, which could be found by optimizing the position of the frozen Pt(111) slab. As it stands, manual sampling of the position of the slab is impractical and betrays the self-consistency of the method. Based on this understanding, we propose the implementation of a free energy optimization scheme of the relative position of the slab in the DFT-RISM boundary region. This optimization scheme could considerably increase the applicability of the hybrid method.

Description: 

The full text of this paper will be available in October 2020 due to the embargo policies of ACS Applied Energy Materials. Contact summit@sfu.ca to enquire if the full text of the accepted manuscript can be made available to you.

Language: 
English
Document type: 
Article
Rights: 
Rights remain with the authors.
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