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Publikationstyp
Wissenschaftlicher Artikel
Erscheinungsjahr
2023
Structural and chemical properties of NiOx thin films: the role of oxygen vacancies in NiOOH formation in a H2O atmosphere
Structural and chemical properties of NiOx thin films: the role of oxygen vacancies in NiOOH formation in a H2O atmosphere
Autor:innen
Herausgeber
Quelle
Physical chemistry, chemical physics
25 (2023)
25 (2023)
Schlagwörter
Finanzierungskennzeichen
standardisiertes Finanzierungskennzeichen
Verbundene Publikation
Zitation
BLUME, A. Raoul, Wolfram CALVET und Aliakbar GHAFARI, 2023. Structural and chemical properties of NiOx thin films: the role of oxygen vacancies in NiOOH formation in a H2O atmosphere. Physical chemistry, chemical physics [online]. 2023. Bd. 25 (2023). DOI 10.60810/openumwelt-1932. Verfügbar unter: https://openumwelt.de/handle/123456789/1359
Zusammenfassung englisch
NiOx films grown from 50 nm thick Ni on Si(111) were put in contact with oxygen and subsequently water vapor at elevated temperatures. Near ambient pressure (NAP)-XPS and -XAS reveal the formation of oxygen vacancies at elevated temperatures, followed by H2O dissociation and saturation of the oxygen vacancies with chemisorbing OH. Through repeated heating and cooling, OH-saturated oxygen vacancies act as precursors for the formation of thermally stable NiOOH on the sample surface. This is accompanied by a significant restructuring of the surface which increases the probability of NiOOH formation. Exposure of a thin NiOx film to H2O can lead to a partial reduction of NiOx to metallic Ni accompanied by a distinct shift of the NiOx spectra with respect to the Fermi edge. DFT calculations show that the formation of oxygen vacancies and subsequently Ni0 leads to a state within the band gap of NiO which pins the Fermi edge. © the Owner Societies 2023