Electro-oxidation of water on hematite: Effects of surface termination and oxygen vacancies investigated by first-principles
Journal article, 2015
The oxygen evolution reaction on hydroxyl- and oxygen-terminated hematite was investigated using first-principle calculations within a theoretical electrochemical framework. Both pristine hematite and hematite containing oxygen vacancies were considered. The onset potential was determined to be 1.79 V and 2.09 V vs. the reversible hydrogen electrode (RHE) for the pristine hydroxyl- and oxygen-terminated hematite, respectively. The presence of oxygen vacancies in the hematite surface resulted in pronounced shifts of the onset potential to 3.09 V and 1.83 V. respectively. Electrochemical oxidation measurements conducted on thin-film hematite anodes, resulted in a measured onset potential of 1.66 V vs. RHE. Furthermore, the threshold potential between the hydroxyl- and oxygen-terminated hematite was determined as a function of pH. The results indicate that electrochemical water oxidation on hematite occurs on the oxygen-terminated hematite, containing oxygen vacancies.
Physics
ab-initio
photoelectrodes
Oxidation
augmented-wave method
generation
Water
oxide
transition
Chemistry
oxidation
Hematite
electrolysis
DFT
initio molecular-dynamics
Electrochemistry
energy
Author
Anders Hellman
Chalmers, Applied Physics, Chemical Physics
Competence Centre for Catalysis (KCK)
Beniamino Iandolo
Chalmers, Applied Physics, Chemical Physics
Björn Wickman
Chalmers, Applied Physics, Chemical Physics
Henrik Grönbeck
Chalmers, Applied Physics, Chemical Physics
Competence Centre for Catalysis (KCK)
J. Baltrusaitis
Lehigh University
Surface Science
0039-6028 (ISSN)
Vol. 640 45-49Subject Categories
Condensed Matter Physics
DOI
10.1016/j.susc.2015.03.022