Stability and chemisorption properties of ultrathin TiOx/Pt(111) films and Au/TiOx/Pt(111) model catalysts in reactive atmospheres

Luca Gavioli, Emanuele Cavaliere, Luca Artiglia, Gaetano Granozzi, Thomas Diemant, Heinrich Hartmann, Joachim Bansmann, R. Jürgen Behm

Risultato della ricerca: Contributo in rivistaArticolo in rivistapeer review

5 Citazioni (Scopus)

Abstract

The stability of three ultrathin TiOx/Pt(111) films with different stoichiometry and defectivity and the corresponding Au/TiOx/Pt(111) model catalysts in CO or a CO-O-2 (1 : 1) gas mixture up to a pressure of 100 mbar has been investigated. According to previous studies, the ultrathin films proved to be effective substrates to deposit in UHV Au nanoparticles with specific morphologies and lateral sizes ranging between 1 and 6 nm. The films have been characterized before and after the exposure using X-ray photoemission spectroscopy (XPS), low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM). Additional in situ measurements of the CO chemisorption behavior were performed using polarization-modulation infrared reflection-absorption spectroscopy (PM-IRAS). A fully oxidized film is stable in CO and CO-O-2 (1 : 1) ambient, while the reduced films undergo an oxidative dewetting process at RT in the latter atmosphere. This process ultimately produces a nano-composite surface, where very tiny (from 0.5 to 3 nm lateral sizes) titania nanograins are mixed with open, uncovered areas of the Pt substrate. IRAS measurements on the corresponding Au/TiOx/Pt(111) model catalysts demonstrated that the CO chemisorption strongly depends on the Au nanoparticle size and morphology, while the actual Ti oxidation state of the oxide support does not seem to play a significant role.
Lingua originaleEnglish
pagine (da-a)6864-6874
Numero di pagine11
RivistaPhysical Chemistry Chemical Physics
Volume12
DOI
Stato di pubblicazionePubblicato - 2010

Keywords

  • Directed-assembly
  • Metal nanoparticles
  • Metal/oxide interaction
  • Oxide layers
  • Templating effect
  • model catalysts
  • morphology
  • redox process

Fingerprint

Entra nei temi di ricerca di 'Stability and chemisorption properties of ultrathin TiOx/Pt(111) films and Au/TiOx/Pt(111) model catalysts in reactive atmospheres'. Insieme formano una fingerprint unica.

Cita questo