Coverage-dependent oxidation and reduction of vanadium supported on anatase TiO2(1 0 1)

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Abstract

© 2018 Elsevier Inc. Using a multi-technical approach, we studied the oxidation of anatase TiO 2 (1 0 1)-supported vanadium (V) clusters at room temperature. We found by ex situ XPS that the highest oxidation state is +4 at sub-monolayer coverage regardless of the O 2 pressure, and STM studies revealed that the initial oxidation proceeds through oxygen-induced disintegration of V clusters into monomeric VO 2 species. By contrast, for ∼2 monolayer V coverage, a partial oxidation to V 5+ is achieved. By in situ APXPS measurements, we found that V can be maintained in the V 5+ oxidation state irrespective of the coverage; however, in the sub-monolayer range, an O 2 pressure of at least ∼1 × 10 −5 mbar is needed. Our results suggest an enhanced reducibility of V in direct contact with the TiO 2 support compared to V in the 2nd layer, which is in line with the observed optimum V 2 O 5 loading in catalytic applications just slightly below a full monolayer.

Detaljer

Författare
  • Stig Koust
  • Benjamin N. Reinecke
  • Kræn C. Adamsen
  • Igor Beinik
  • Karsten Handrup
  • Zheshen Li
  • Poul G. Moses
  • Joachim Schnadt
  • Jeppe V. Lauritsen
  • Stefan Wendt
Enheter & grupper
Externa organisationer
  • Aarhus University
  • Lund University
  • Haldor Topsøe A/S
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Annan kemiteknik

Nyckelord

Originalspråkengelska
Sidor (från-till)118-126
Antal sidor9
TidskriftJournal of Catalysis
Volym360
StatusPublished - 2018 apr 1
PublikationskategoriForskning
Peer review utfördJa