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Electro-oxidation of water on hematite: Effects of surface termination and oxygen vacancies investigated by first-principles

Anders Hellman (Institutionen för teknisk fysik, Kemisk fysik ; Kompetenscentrum katalys (KCK)) ; Beniamino Iandolo (Institutionen för teknisk fysik, Kemisk fysik) ; Björn Wickman (Institutionen för teknisk fysik, Kemisk fysik) ; Henrik Grönbeck (Institutionen för teknisk fysik, Kemisk fysik ; Kompetenscentrum katalys (KCK)) ; J. Baltrusaitis
Surface Science (0039-6028). Vol. 640 (2015), p. 45-49.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: Electrochemistry, Hematite, Water, Oxidation, DFT, initio molecular-dynamics, augmented-wave method, ab-initio, electrolysis, oxidation, energy, oxide, photoelectrodes, transition, generation, Chemistry, Physics



Denna post skapades 2015-09-03. Senast ändrad 2016-07-04.
CPL Pubid: 221871

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kemisk fysik (1900-2015)
Kompetenscentrum katalys (KCK)

Ämnesområden

Den kondenserade materiens fysik

Chalmers infrastruktur