Open AccessOxygen Evolution at Hematite Surfaces: The Impact of Structure and Oxygen Vacancies on Lowering the Overpotential
Author(s) -
Xueqing Zhang,
Peter Klaver,
Rutger A. van Santen,
M. C. M. van de Sanden,
Anja BieberleHütter
Publication year - 2016
Publication title -
the journal of physical chemistry c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.6b07228
Subject(s) - overpotential , oxygen evolution , vacancy defect , oxygen , density functional theory , water splitting , chemistry , chemical physics , materials science , inorganic chemistry , catalysis , crystallography , computational chemistry , biochemistry , organic chemistry , electrode , photocatalysis , electrochemistry
Simulations of the oxygen evolution reaction (OER) are essential for understanding the limitations of water splitting. Most research has focused so far on the OER at flat metal oxide surfaces. The structure sensitivity of the OER has, however, recently been highlighted as a promising research direction. To probe the structure sensitivity, we investigate the OER at 11 hematite (Fe2O3) surfaces with density functional theory + Hubbard U (DFT+U) calculations. The results show that the O–O coupling (O–O bond formation via two adjacent terminal Os at dual site) OER mechanism at the (110) surface is competing with the mechanism of OOH formation at single site. We study the effects of surface orientation (110 vs 104), active surface sites (bridge vs terminal site), presence of surface steps and oxygen vacancy concentration on the OER and explore strategies to reduce the OER overpotential. It is found that the oxygen vacancy concentration is the most effective parameter in reducing the overpotential. In particula...
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