Abstract
The evolution of a Fe/z'-TiOx/Pt(111) model catalyst in ultrahigh vacuum, studied by advanced surface science tools, reveals various phenomena occurring in different temperature ranges. In the room temperature (RT) < T < 460 K range, the deposited Fe atoms assemble as heterogeneous Fe and FeOx nanoparticles (NPs), templated by the ordered array of defects (troughs and picoholes) of the oxide film. At 460 < T < 810 K, FeOx NPs become predominant, and a metastable FeOx/TiOx mixed oxide is formed, assisted by the interdiffusion of Fe through the oxide into the Pt substrate, which triggers the z'-TiOx structure transformation into a different TiOx phase with a hexagonal pattern. At 810 < T < 1000 K, a Fe-mediated extraction of Pt produces Pt(111) islands, surrounded and partly encapsulated by the same z'-TiOx phase,
demonstrating the intrinsic high stability of the ultrathin oxide film.
This represents one of the first examples of a phase transformation in a ultrathin oxide layer induced by an external metal deposit.
Lingua originale | English |
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pagine (da-a) | 1660-1665 |
Numero di pagine | 6 |
Rivista | THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS |
Volume | 2010 |
DOI | |
Stato di pubblicazione | Pubblicato - 2010 |
Keywords
- Catalysis
- Defects
- Directed-assembly
- Fe nanoparticles
- Metal/oxide interaction
- Oxide layers
- Templating effect