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Title: Towards First Principles-Based Prediction of Highly Accurate Electrochemical Pourbaix Diagrams

Abstract

Electrochemical potential/pH (Pourbaix) diagrams underpin many aqueous electrochemical processes and are central to the identification of stable phases of metals for processes ranging from electrocatalysis to corrosion. Even though standard DFT calculations are potentially powerful tools for the prediction of such diagrams, inherent errors in the description of transition metal (hydroxy)oxides, together with neglect of van der Waals interactions, have limited the reliability of such predictions for even the simplest pure metal bulk compounds, and corresponding predictions for more complex alloy or surface structures are even more challenging. In the present work, through synergistic use of a Hubbard U correction, a state-of-the-art dispersion correction, and a water-based bulk reference state for the calculations, these errors are systematically corrected. The approach describes the weak binding that occurs between hydroxyl-containing functional groups in certain compounds in Pourbaix diagrams, corrects for self-interaction errors in transition metal compounds, and reduces residual errors on oxygen atoms by preserving a consistent oxidation state between the reference state, water, and the relevant bulk phases. The strong performance is illustrated on a series of bulk transition metal (Mn, Fe, Co and Ni) hydroxides, oxyhydroxides, binary, and ternary oxides, where the corresponding thermodynamics of redox and (de)hydration are describedmore » with standard errors of 0.04 eV per (reaction) formula unit. The approach further preserves accurate descriptions of the overall thermodynamics of electrochemically-relevant bulk reactions, such as water formation, which is an essential condition for facilitating accurate analysis of reaction energies for electrochemical processes on surfaces. The overall generality and transferability of the scheme suggests that it may find useful application in the construction of a broad array of electrochemical phase diagrams, including both bulk Pourbaix diagrams and surface phase diagrams of interest for corrosion and electrocatalysis.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1390935
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 119; Journal Issue: 32; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Density Functional Theory; Pourbaix diagrams; stability; transition metals; van der Waals

Citation Formats

Zeng, Zhenhua, Chan, Maria K. Y., Zhao, Zhi-Jian, Kubal, Joseph, Fan, Dingxin, and Greeley, Jeffrey. Towards First Principles-Based Prediction of Highly Accurate Electrochemical Pourbaix Diagrams. United States: N. p., 2015. Web. doi:10.1021/acs.jpcc.5b03169.
Zeng, Zhenhua, Chan, Maria K. Y., Zhao, Zhi-Jian, Kubal, Joseph, Fan, Dingxin, & Greeley, Jeffrey. Towards First Principles-Based Prediction of Highly Accurate Electrochemical Pourbaix Diagrams. United States. doi:10.1021/acs.jpcc.5b03169.
Zeng, Zhenhua, Chan, Maria K. Y., Zhao, Zhi-Jian, Kubal, Joseph, Fan, Dingxin, and Greeley, Jeffrey. Thu . "Towards First Principles-Based Prediction of Highly Accurate Electrochemical Pourbaix Diagrams". United States. doi:10.1021/acs.jpcc.5b03169.
@article{osti_1390935,
title = {Towards First Principles-Based Prediction of Highly Accurate Electrochemical Pourbaix Diagrams},
author = {Zeng, Zhenhua and Chan, Maria K. Y. and Zhao, Zhi-Jian and Kubal, Joseph and Fan, Dingxin and Greeley, Jeffrey},
abstractNote = {Electrochemical potential/pH (Pourbaix) diagrams underpin many aqueous electrochemical processes and are central to the identification of stable phases of metals for processes ranging from electrocatalysis to corrosion. Even though standard DFT calculations are potentially powerful tools for the prediction of such diagrams, inherent errors in the description of transition metal (hydroxy)oxides, together with neglect of van der Waals interactions, have limited the reliability of such predictions for even the simplest pure metal bulk compounds, and corresponding predictions for more complex alloy or surface structures are even more challenging. In the present work, through synergistic use of a Hubbard U correction, a state-of-the-art dispersion correction, and a water-based bulk reference state for the calculations, these errors are systematically corrected. The approach describes the weak binding that occurs between hydroxyl-containing functional groups in certain compounds in Pourbaix diagrams, corrects for self-interaction errors in transition metal compounds, and reduces residual errors on oxygen atoms by preserving a consistent oxidation state between the reference state, water, and the relevant bulk phases. The strong performance is illustrated on a series of bulk transition metal (Mn, Fe, Co and Ni) hydroxides, oxyhydroxides, binary, and ternary oxides, where the corresponding thermodynamics of redox and (de)hydration are described with standard errors of 0.04 eV per (reaction) formula unit. The approach further preserves accurate descriptions of the overall thermodynamics of electrochemically-relevant bulk reactions, such as water formation, which is an essential condition for facilitating accurate analysis of reaction energies for electrochemical processes on surfaces. The overall generality and transferability of the scheme suggests that it may find useful application in the construction of a broad array of electrochemical phase diagrams, including both bulk Pourbaix diagrams and surface phase diagrams of interest for corrosion and electrocatalysis.},
doi = {10.1021/acs.jpcc.5b03169},
journal = {Journal of Physical Chemistry. C},
issn = {1932-7447},
number = 32,
volume = 119,
place = {United States},
year = {2015},
month = {8}
}